diff --git a/stb_image.h b/stb_image.h
index 8b71060..d0aaf2a 100644
--- a/stb_image.h
+++ b/stb_image.h
@@ -1,4 +1,4 @@
-/* stb_image - v2.21 - public domain image loader - http://nothings.org/stb
+/* stb_image - v2.28 - public domain image loader - http://nothings.org/stb
                                   no warranty implied; use at your own risk
 
    Do this:
@@ -48,8 +48,15 @@
 
 RECENT REVISION HISTORY:
 
+      2.28  (2023-01-29) many error fixes, security errors, just tons of stuff
+      2.27  (2021-07-11) document stbi_info better, 16-bit PNM support, bug fixes
+      2.26  (2020-07-13) many minor fixes
+      2.25  (2020-02-02) fix warnings
+      2.24  (2020-02-02) fix warnings; thread-local failure_reason and flip_vertically
+      2.23  (2019-08-11) fix clang static analysis warning
+      2.22  (2019-03-04) gif fixes, fix warnings
       2.21  (2019-02-25) fix typo in comment
-      2.20  (2019-02-07) support utf8 filenames in Windows; fix warnings and platform ifdefs 
+      2.20  (2019-02-07) support utf8 filenames in Windows; fix warnings and platform ifdefs
       2.19  (2018-02-11) fix warning
       2.18  (2018-01-30) fix warnings
       2.17  (2018-01-29) bugfix, 1-bit BMP, 16-bitness query, fix warnings
@@ -84,26 +91,37 @@
                                            Jeremy Sawicki (handle all ImageNet JPGs)
  Optimizations & bugfixes                  Mikhail Morozov (1-bit BMP)
     Fabian "ryg" Giesen                    Anael Seghezzi (is-16-bit query)
-    Arseny Kapoulkine
+    Arseny Kapoulkine                      Simon Breuss (16-bit PNM)
     John-Mark Allen
     Carmelo J Fdez-Aguera
 
  Bug & warning fixes
-    Marc LeBlanc            David Woo          Guillaume George   Martins Mozeiko
-    Christpher Lloyd        Jerry Jansson      Joseph Thomson     Phil Jordan
-    Dave Moore              Roy Eltham         Hayaki Saito       Nathan Reed
-    Won Chun                Luke Graham        Johan Duparc       Nick Verigakis
-    the Horde3D community   Thomas Ruf         Ronny Chevalier    github:rlyeh
-    Janez Zemva             John Bartholomew   Michal Cichon      github:romigrou
-    Jonathan Blow           Ken Hamada         Tero Hanninen      github:svdijk
-    Laurent Gomila          Cort Stratton      Sergio Gonzalez    github:snagar
-    Aruelien Pocheville     Thibault Reuille   Cass Everitt       github:Zelex
-    Ryamond Barbiero        Paul Du Bois       Engin Manap        github:grim210
-    Aldo Culquicondor       Philipp Wiesemann  Dale Weiler        github:sammyhw
-    Oriol Ferrer Mesia      Josh Tobin         Matthew Gregan     github:phprus
-    Julian Raschke          Gregory Mullen     Baldur Karlsson    github:poppolopoppo
-    Christian Floisand      Kevin Schmidt      JR Smith           github:darealshinji
-    Blazej Dariusz Roszkowski                                     github:Michaelangel007
+    Marc LeBlanc            David Woo          Guillaume George     Martins Mozeiko
+    Christpher Lloyd        Jerry Jansson      Joseph Thomson       Blazej Dariusz Roszkowski
+    Phil Jordan                                Dave Moore           Roy Eltham
+    Hayaki Saito            Nathan Reed        Won Chun
+    Luke Graham             Johan Duparc       Nick Verigakis       the Horde3D community
+    Thomas Ruf              Ronny Chevalier                         github:rlyeh
+    Janez Zemva             John Bartholomew   Michal Cichon        github:romigrou
+    Jonathan Blow           Ken Hamada         Tero Hanninen        github:svdijk
+    Eugene Golushkov        Laurent Gomila     Cort Stratton        github:snagar
+    Aruelien Pocheville     Sergio Gonzalez    Thibault Reuille     github:Zelex
+    Cass Everitt            Ryamond Barbiero                        github:grim210
+    Paul Du Bois            Engin Manap        Aldo Culquicondor    github:sammyhw
+    Philipp Wiesemann       Dale Weiler        Oriol Ferrer Mesia   github:phprus
+    Josh Tobin              Neil Bickford      Matthew Gregan       github:poppolopoppo
+    Julian Raschke          Gregory Mullen     Christian Floisand   github:darealshinji
+    Baldur Karlsson         Kevin Schmidt      JR Smith             github:Michaelangel007
+                            Brad Weinberger    Matvey Cherevko      github:mosra
+    Luca Sas                Alexander Veselov  Zack Middleton       [reserved]
+    Ryan C. Gordon          [reserved]                              [reserved]
+                     DO NOT ADD YOUR NAME HERE
+
+                     Jacko Dirks
+
+  To add your name to the credits, pick a random blank space in the middle and fill it.
+  80% of merge conflicts on stb PRs are due to people adding their name at the end
+  of the credits.
 */
 
 #ifndef STBI_INCLUDE_STB_IMAGE_H
@@ -123,7 +141,7 @@
 //    // ... x = width, y = height, n = # 8-bit components per pixel ...
 //    // ... replace '0' with '1'..'4' to force that many components per pixel
 //    // ... but 'n' will always be the number that it would have been if you said 0
-//    stbi_image_free(data)
+//    stbi_image_free(data);
 //
 // Standard parameters:
 //    int *x                 -- outputs image width in pixels
@@ -162,6 +180,32 @@
 //
 // Paletted PNG, BMP, GIF, and PIC images are automatically depalettized.
 //
+// To query the width, height and component count of an image without having to
+// decode the full file, you can use the stbi_info family of functions:
+//
+//   int x,y,n,ok;
+//   ok = stbi_info(filename, &x, &y, &n);
+//   // returns ok=1 and sets x, y, n if image is a supported format,
+//   // 0 otherwise.
+//
+// Note that stb_image pervasively uses ints in its public API for sizes,
+// including sizes of memory buffers. This is now part of the API and thus
+// hard to change without causing breakage. As a result, the various image
+// loaders all have certain limits on image size; these differ somewhat
+// by format but generally boil down to either just under 2GB or just under
+// 1GB. When the decoded image would be larger than this, stb_image decoding
+// will fail.
+//
+// Additionally, stb_image will reject image files that have any of their
+// dimensions set to a larger value than the configurable STBI_MAX_DIMENSIONS,
+// which defaults to 2**24 = 16777216 pixels. Due to the above memory limit,
+// the only way to have an image with such dimensions load correctly
+// is for it to have a rather extreme aspect ratio. Either way, the
+// assumption here is that such larger images are likely to be malformed
+// or malicious. If you do need to load an image with individual dimensions
+// larger than that, and it still fits in the overall size limit, you can
+// #define STBI_MAX_DIMENSIONS on your own to be something larger.
+//
 // ===========================================================================
 //
 // UNICODE:
@@ -267,11 +311,10 @@
 //
 // iPhone PNG support:
 //
-// By default we convert iphone-formatted PNGs back to RGB, even though
-// they are internally encoded differently. You can disable this conversion
-// by calling stbi_convert_iphone_png_to_rgb(0), in which case
-// you will always just get the native iphone "format" through (which
-// is BGR stored in RGB).
+// We optionally support converting iPhone-formatted PNGs (which store
+// premultiplied BGRA) back to RGB, even though they're internally encoded
+// differently. To enable this conversion, call
+// stbi_convert_iphone_png_to_rgb(1).
 //
 // Call stbi_set_unpremultiply_on_load(1) as well to force a divide per
 // pixel to remove any premultiplied alpha *only* if the image file explicitly
@@ -313,7 +356,14 @@
 //   - If you use STBI_NO_PNG (or _ONLY_ without PNG), and you still
 //     want the zlib decoder to be available, #define STBI_SUPPORT_ZLIB
 //
-
+//  - If you define STBI_MAX_DIMENSIONS, stb_image will reject images greater
+//    than that size (in either width or height) without further processing.
+//    This is to let programs in the wild set an upper bound to prevent
+//    denial-of-service attacks on untrusted data, as one could generate a
+//    valid image of gigantic dimensions and force stb_image to allocate a
+//    huge block of memory and spend disproportionate time decoding it. By
+//    default this is set to (1 << 24), which is 16777216, but that's still
+//    very big.
 
 #ifndef STBI_NO_STDIO
 #include <stdio.h>
@@ -339,11 +389,13 @@
 extern "C" {
 #endif
 
+#ifndef STBIDEF
 #ifdef STB_IMAGE_STATIC
 #define STBIDEF static
 #else
 #define STBIDEF extern
 #endif
+#endif
 
 //////////////////////////////////////////////////////////////////////////////
 //
@@ -430,7 +482,7 @@
 
 
 // get a VERY brief reason for failure
-// NOT THREADSAFE
+// on most compilers (and ALL modern mainstream compilers) this is threadsafe
 STBIDEF const char *stbi_failure_reason  (void);
 
 // free the loaded image -- this is just free()
@@ -463,6 +515,13 @@
 // flip the image vertically, so the first pixel in the output array is the bottom left
 STBIDEF void stbi_set_flip_vertically_on_load(int flag_true_if_should_flip);
 
+// as above, but only applies to images loaded on the thread that calls the function
+// this function is only available if your compiler supports thread-local variables;
+// calling it will fail to link if your compiler doesn't
+STBIDEF void stbi_set_unpremultiply_on_load_thread(int flag_true_if_should_unpremultiply);
+STBIDEF void stbi_convert_iphone_png_to_rgb_thread(int flag_true_if_should_convert);
+STBIDEF void stbi_set_flip_vertically_on_load_thread(int flag_true_if_should_flip);
+
 // ZLIB client - used by PNG, available for other purposes
 
 STBIDEF char *stbi_zlib_decode_malloc_guesssize(const char *buffer, int len, int initial_size, int *outlen);
@@ -559,8 +618,25 @@
    #define stbi_inline __forceinline
 #endif
 
+#ifndef STBI_NO_THREAD_LOCALS
+   #if defined(__cplusplus) &&  __cplusplus >= 201103L
+      #define STBI_THREAD_LOCAL       thread_local
+   #elif defined(__GNUC__) && __GNUC__ < 5
+      #define STBI_THREAD_LOCAL       __thread
+   #elif defined(_MSC_VER)
+      #define STBI_THREAD_LOCAL       __declspec(thread)
+   #elif defined (__STDC_VERSION__) && __STDC_VERSION__ >= 201112L && !defined(__STDC_NO_THREADS__)
+      #define STBI_THREAD_LOCAL       _Thread_local
+   #endif
 
-#ifdef _MSC_VER
+   #ifndef STBI_THREAD_LOCAL
+      #if defined(__GNUC__)
+        #define STBI_THREAD_LOCAL       __thread
+      #endif
+   #endif
+#endif
+
+#if defined(_MSC_VER) || defined(__SYMBIAN32__)
 typedef unsigned short stbi__uint16;
 typedef   signed short stbi__int16;
 typedef unsigned int   stbi__uint32;
@@ -589,7 +665,7 @@
 #ifdef STBI_HAS_LROTL
    #define stbi_lrot(x,y)  _lrotl(x,y)
 #else
-   #define stbi_lrot(x,y)  (((x) << (y)) | ((x) >> (32 - (y))))
+   #define stbi_lrot(x,y)  (((x) << (y)) | ((x) >> (-(y) & 31)))
 #endif
 
 #if defined(STBI_MALLOC) && defined(STBI_FREE) && (defined(STBI_REALLOC) || defined(STBI_REALLOC_SIZED))
@@ -703,14 +779,21 @@
 
 #ifdef STBI_NEON
 #include <arm_neon.h>
-// assume GCC or Clang on ARM targets
+#ifdef _MSC_VER
+#define STBI_SIMD_ALIGN(type, name) __declspec(align(16)) type name
+#else
 #define STBI_SIMD_ALIGN(type, name) type name __attribute__((aligned(16)))
 #endif
+#endif
 
 #ifndef STBI_SIMD_ALIGN
 #define STBI_SIMD_ALIGN(type, name) type name
 #endif
 
+#ifndef STBI_MAX_DIMENSIONS
+#define STBI_MAX_DIMENSIONS (1 << 24)
+#endif
+
 ///////////////////////////////////////////////
 //
 //  stbi__context struct and start_xxx functions
@@ -728,6 +811,7 @@
    int read_from_callbacks;
    int buflen;
    stbi_uc buffer_start[128];
+   int callback_already_read;
 
    stbi_uc *img_buffer, *img_buffer_end;
    stbi_uc *img_buffer_original, *img_buffer_original_end;
@@ -741,6 +825,7 @@
 {
    s->io.read = NULL;
    s->read_from_callbacks = 0;
+   s->callback_already_read = 0;
    s->img_buffer = s->img_buffer_original = (stbi_uc *) buffer;
    s->img_buffer_end = s->img_buffer_original_end = (stbi_uc *) buffer+len;
 }
@@ -752,7 +837,8 @@
    s->io_user_data = user;
    s->buflen = sizeof(s->buffer_start);
    s->read_from_callbacks = 1;
-   s->img_buffer_original = s->buffer_start;
+   s->callback_already_read = 0;
+   s->img_buffer = s->img_buffer_original = s->buffer_start;
    stbi__refill_buffer(s);
    s->img_buffer_original_end = s->img_buffer_end;
 }
@@ -766,12 +852,17 @@
 
 static void stbi__stdio_skip(void *user, int n)
 {
+   int ch;
    fseek((FILE*) user, n, SEEK_CUR);
+   ch = fgetc((FILE*) user);  /* have to read a byte to reset feof()'s flag */
+   if (ch != EOF) {
+      ungetc(ch, (FILE *) user);  /* push byte back onto stream if valid. */
+   }
 }
 
 static int stbi__stdio_eof(void *user)
 {
-   return feof((FILE*) user);
+   return feof((FILE*) user) || ferror((FILE *) user);
 }
 
 static stbi_io_callbacks stbi__stdio_callbacks =
@@ -867,21 +958,27 @@
 static int      stbi__pnm_test(stbi__context *s);
 static void    *stbi__pnm_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
 static int      stbi__pnm_info(stbi__context *s, int *x, int *y, int *comp);
+static int      stbi__pnm_is16(stbi__context *s);
 #endif
 
-// this is not threadsafe
-static const char *stbi__g_failure_reason;
+static
+#ifdef STBI_THREAD_LOCAL
+STBI_THREAD_LOCAL
+#endif
+const char *stbi__g_failure_reason;
 
 STBIDEF const char *stbi_failure_reason(void)
 {
    return stbi__g_failure_reason;
 }
 
+#ifndef STBI_NO_FAILURE_STRINGS
 static int stbi__err(const char *str)
 {
    stbi__g_failure_reason = str;
    return 0;
 }
+#endif
 
 static void *stbi__malloc(size_t size)
 {
@@ -920,11 +1017,13 @@
    return a <= INT_MAX/b;
 }
 
+#if !defined(STBI_NO_JPEG) || !defined(STBI_NO_PNG) || !defined(STBI_NO_TGA) || !defined(STBI_NO_HDR)
 // returns 1 if "a*b + add" has no negative terms/factors and doesn't overflow
 static int stbi__mad2sizes_valid(int a, int b, int add)
 {
    return stbi__mul2sizes_valid(a, b) && stbi__addsizes_valid(a*b, add);
 }
+#endif
 
 // returns 1 if "a*b*c + add" has no negative terms/factors and doesn't overflow
 static int stbi__mad3sizes_valid(int a, int b, int c, int add)
@@ -934,7 +1033,7 @@
 }
 
 // returns 1 if "a*b*c*d + add" has no negative terms/factors and doesn't overflow
-#if !defined(STBI_NO_LINEAR) || !defined(STBI_NO_HDR)
+#if !defined(STBI_NO_LINEAR) || !defined(STBI_NO_HDR) || !defined(STBI_NO_PNM)
 static int stbi__mad4sizes_valid(int a, int b, int c, int d, int add)
 {
    return stbi__mul2sizes_valid(a, b) && stbi__mul2sizes_valid(a*b, c) &&
@@ -942,12 +1041,14 @@
 }
 #endif
 
+#if !defined(STBI_NO_JPEG) || !defined(STBI_NO_PNG) || !defined(STBI_NO_TGA) || !defined(STBI_NO_HDR)
 // mallocs with size overflow checking
 static void *stbi__malloc_mad2(int a, int b, int add)
 {
    if (!stbi__mad2sizes_valid(a, b, add)) return NULL;
    return stbi__malloc(a*b + add);
 }
+#endif
 
 static void *stbi__malloc_mad3(int a, int b, int c, int add)
 {
@@ -955,7 +1056,7 @@
    return stbi__malloc(a*b*c + add);
 }
 
-#if !defined(STBI_NO_LINEAR) || !defined(STBI_NO_HDR)
+#if !defined(STBI_NO_LINEAR) || !defined(STBI_NO_HDR) || !defined(STBI_NO_PNM)
 static void *stbi__malloc_mad4(int a, int b, int c, int d, int add)
 {
    if (!stbi__mad4sizes_valid(a, b, c, d, add)) return NULL;
@@ -963,6 +1064,23 @@
 }
 #endif
 
+// returns 1 if the sum of two signed ints is valid (between -2^31 and 2^31-1 inclusive), 0 on overflow.
+static int stbi__addints_valid(int a, int b)
+{
+   if ((a >= 0) != (b >= 0)) return 1; // a and b have different signs, so no overflow
+   if (a < 0 && b < 0) return a >= INT_MIN - b; // same as a + b >= INT_MIN; INT_MIN - b cannot overflow since b < 0.
+   return a <= INT_MAX - b;
+}
+
+// returns 1 if the product of two signed shorts is valid, 0 on overflow.
+static int stbi__mul2shorts_valid(short a, short b)
+{
+   if (b == 0 || b == -1) return 1; // multiplication by 0 is always 0; check for -1 so SHRT_MIN/b doesn't overflow
+   if ((a >= 0) == (b >= 0)) return a <= SHRT_MAX/b; // product is positive, so similar to mul2sizes_valid
+   if (b < 0) return a <= SHRT_MIN / b; // same as a * b >= SHRT_MIN
+   return a >= SHRT_MIN / b;
+}
+
 // stbi__err - error
 // stbi__errpf - error returning pointer to float
 // stbi__errpuc - error returning pointer to unsigned char
@@ -991,13 +1109,29 @@
 static stbi_uc *stbi__hdr_to_ldr(float   *data, int x, int y, int comp);
 #endif
 
-static int stbi__vertically_flip_on_load = 0;
+static int stbi__vertically_flip_on_load_global = 0;
 
 STBIDEF void stbi_set_flip_vertically_on_load(int flag_true_if_should_flip)
 {
-    stbi__vertically_flip_on_load = flag_true_if_should_flip;
+   stbi__vertically_flip_on_load_global = flag_true_if_should_flip;
 }
 
+#ifndef STBI_THREAD_LOCAL
+#define stbi__vertically_flip_on_load  stbi__vertically_flip_on_load_global
+#else
+static STBI_THREAD_LOCAL int stbi__vertically_flip_on_load_local, stbi__vertically_flip_on_load_set;
+
+STBIDEF void stbi_set_flip_vertically_on_load_thread(int flag_true_if_should_flip)
+{
+   stbi__vertically_flip_on_load_local = flag_true_if_should_flip;
+   stbi__vertically_flip_on_load_set = 1;
+}
+
+#define stbi__vertically_flip_on_load  (stbi__vertically_flip_on_load_set       \
+                                         ? stbi__vertically_flip_on_load_local  \
+                                         : stbi__vertically_flip_on_load_global)
+#endif // STBI_THREAD_LOCAL
+
 static void *stbi__load_main(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri, int bpc)
 {
    memset(ri, 0, sizeof(*ri)); // make sure it's initialized if we add new fields
@@ -1005,9 +1139,8 @@
    ri->channel_order = STBI_ORDER_RGB; // all current input & output are this, but this is here so we can add BGR order
    ri->num_channels = 0;
 
-   #ifndef STBI_NO_JPEG
-   if (stbi__jpeg_test(s)) return stbi__jpeg_load(s,x,y,comp,req_comp, ri);
-   #endif
+   // test the formats with a very explicit header first (at least a FOURCC
+   // or distinctive magic number first)
    #ifndef STBI_NO_PNG
    if (stbi__png_test(s))  return stbi__png_load(s,x,y,comp,req_comp, ri);
    #endif
@@ -1019,10 +1152,19 @@
    #endif
    #ifndef STBI_NO_PSD
    if (stbi__psd_test(s))  return stbi__psd_load(s,x,y,comp,req_comp, ri, bpc);
+   #else
+   STBI_NOTUSED(bpc);
    #endif
    #ifndef STBI_NO_PIC
    if (stbi__pic_test(s))  return stbi__pic_load(s,x,y,comp,req_comp, ri);
    #endif
+
+   // then the formats that can end up attempting to load with just 1 or 2
+   // bytes matching expectations; these are prone to false positives, so
+   // try them later
+   #ifndef STBI_NO_JPEG
+   if (stbi__jpeg_test(s)) return stbi__jpeg_load(s,x,y,comp,req_comp, ri);
+   #endif
    #ifndef STBI_NO_PNM
    if (stbi__pnm_test(s))  return stbi__pnm_load(s,x,y,comp,req_comp, ri);
    #endif
@@ -1107,8 +1249,8 @@
 
    stbi_uc *bytes = (stbi_uc *)image;
    for (slice = 0; slice < z; ++slice) {
-      stbi__vertical_flip(bytes, w, h, bytes_per_pixel); 
-      bytes += slice_size; 
+      stbi__vertical_flip(bytes, w, h, bytes_per_pixel);
+      bytes += slice_size;
    }
 }
 #endif
@@ -1121,8 +1263,10 @@
    if (result == NULL)
       return NULL;
 
+   // it is the responsibility of the loaders to make sure we get either 8 or 16 bit.
+   STBI_ASSERT(ri.bits_per_channel == 8 || ri.bits_per_channel == 16);
+
    if (ri.bits_per_channel != 8) {
-      STBI_ASSERT(ri.bits_per_channel == 16);
       result = stbi__convert_16_to_8((stbi__uint16 *) result, *x, *y, req_comp == 0 ? *comp : req_comp);
       ri.bits_per_channel = 8;
    }
@@ -1145,8 +1289,10 @@
    if (result == NULL)
       return NULL;
 
+   // it is the responsibility of the loaders to make sure we get either 8 or 16 bit.
+   STBI_ASSERT(ri.bits_per_channel == 8 || ri.bits_per_channel == 16);
+
    if (ri.bits_per_channel != 16) {
-      STBI_ASSERT(ri.bits_per_channel == 8);
       result = stbi__convert_8_to_16((stbi_uc *) result, *x, *y, req_comp == 0 ? *comp : req_comp);
       ri.bits_per_channel = 16;
    }
@@ -1174,31 +1320,31 @@
 
 #ifndef STBI_NO_STDIO
 
-#if defined(_MSC_VER) && defined(STBI_WINDOWS_UTF8)
+#if defined(_WIN32) && defined(STBI_WINDOWS_UTF8)
 STBI_EXTERN __declspec(dllimport) int __stdcall MultiByteToWideChar(unsigned int cp, unsigned long flags, const char *str, int cbmb, wchar_t *widestr, int cchwide);
 STBI_EXTERN __declspec(dllimport) int __stdcall WideCharToMultiByte(unsigned int cp, unsigned long flags, const wchar_t *widestr, int cchwide, char *str, int cbmb, const char *defchar, int *used_default);
 #endif
 
-#if defined(_MSC_VER) && defined(STBI_WINDOWS_UTF8)
+#if defined(_WIN32) && defined(STBI_WINDOWS_UTF8)
 STBIDEF int stbi_convert_wchar_to_utf8(char *buffer, size_t bufferlen, const wchar_t* input)
 {
-	return WideCharToMultiByte(65001 /* UTF8 */, 0, input, -1, buffer, bufferlen, NULL, NULL);
+	return WideCharToMultiByte(65001 /* UTF8 */, 0, input, -1, buffer, (int) bufferlen, NULL, NULL);
 }
 #endif
 
 static FILE *stbi__fopen(char const *filename, char const *mode)
 {
    FILE *f;
-#if defined(_MSC_VER) && defined(STBI_WINDOWS_UTF8)
+#if defined(_WIN32) && defined(STBI_WINDOWS_UTF8)
    wchar_t wMode[64];
    wchar_t wFilename[1024];
-	if (0 == MultiByteToWideChar(65001 /* UTF8 */, 0, filename, -1, wFilename, sizeof(wFilename)))
-      return 0;
-	
-	if (0 == MultiByteToWideChar(65001 /* UTF8 */, 0, mode, -1, wMode, sizeof(wMode)))
+	if (0 == MultiByteToWideChar(65001 /* UTF8 */, 0, filename, -1, wFilename, sizeof(wFilename)/sizeof(*wFilename)))
       return 0;
 
-#if _MSC_VER >= 1400
+	if (0 == MultiByteToWideChar(65001 /* UTF8 */, 0, mode, -1, wMode, sizeof(wMode)/sizeof(*wMode)))
+      return 0;
+
+#if defined(_MSC_VER) && _MSC_VER >= 1400
 	if (0 != _wfopen_s(&f, wFilename, wMode))
 		f = 0;
 #else
@@ -1296,15 +1442,15 @@
 STBIDEF stbi_uc *stbi_load_gif_from_memory(stbi_uc const *buffer, int len, int **delays, int *x, int *y, int *z, int *comp, int req_comp)
 {
    unsigned char *result;
-   stbi__context s; 
-   stbi__start_mem(&s,buffer,len); 
-   
+   stbi__context s;
+   stbi__start_mem(&s,buffer,len);
+
    result = (unsigned char*) stbi__load_gif_main(&s, delays, x, y, z, comp, req_comp);
    if (stbi__vertically_flip_on_load) {
-      stbi__vertical_flip_slices( result, *x, *y, *z, *comp ); 
+      stbi__vertical_flip_slices( result, *x, *y, *z, *comp );
    }
 
-   return result; 
+   return result;
 }
 #endif
 
@@ -1449,6 +1595,7 @@
 static void stbi__refill_buffer(stbi__context *s)
 {
    int n = (s->io.read)(s->io_user_data,(char*)s->buffer_start,s->buflen);
+   s->callback_already_read += (int) (s->img_buffer - s->img_buffer_original);
    if (n == 0) {
       // at end of file, treat same as if from memory, but need to handle case
       // where s->img_buffer isn't pointing to safe memory, e.g. 0-byte file
@@ -1473,6 +1620,9 @@
    return 0;
 }
 
+#if defined(STBI_NO_JPEG) && defined(STBI_NO_HDR) && defined(STBI_NO_PIC) && defined(STBI_NO_PNM)
+// nothing
+#else
 stbi_inline static int stbi__at_eof(stbi__context *s)
 {
    if (s->io.read) {
@@ -1484,9 +1634,14 @@
 
    return s->img_buffer >= s->img_buffer_end;
 }
+#endif
 
+#if defined(STBI_NO_JPEG) && defined(STBI_NO_PNG) && defined(STBI_NO_BMP) && defined(STBI_NO_PSD) && defined(STBI_NO_TGA) && defined(STBI_NO_GIF) && defined(STBI_NO_PIC)
+// nothing
+#else
 static void stbi__skip(stbi__context *s, int n)
 {
+   if (n == 0) return;  // already there!
    if (n < 0) {
       s->img_buffer = s->img_buffer_end;
       return;
@@ -1501,7 +1656,11 @@
    }
    s->img_buffer += n;
 }
+#endif
 
+#if defined(STBI_NO_PNG) && defined(STBI_NO_TGA) && defined(STBI_NO_HDR) && defined(STBI_NO_PNM)
+// nothing
+#else
 static int stbi__getn(stbi__context *s, stbi_uc *buffer, int n)
 {
    if (s->io.read) {
@@ -1525,18 +1684,27 @@
    } else
       return 0;
 }
+#endif
 
+#if defined(STBI_NO_JPEG) && defined(STBI_NO_PNG) && defined(STBI_NO_PSD) && defined(STBI_NO_PIC)
+// nothing
+#else
 static int stbi__get16be(stbi__context *s)
 {
    int z = stbi__get8(s);
    return (z << 8) + stbi__get8(s);
 }
+#endif
 
+#if defined(STBI_NO_PNG) && defined(STBI_NO_PSD) && defined(STBI_NO_PIC)
+// nothing
+#else
 static stbi__uint32 stbi__get32be(stbi__context *s)
 {
    stbi__uint32 z = stbi__get16be(s);
    return (z << 16) + stbi__get16be(s);
 }
+#endif
 
 #if defined(STBI_NO_BMP) && defined(STBI_NO_TGA) && defined(STBI_NO_GIF)
 // nothing
@@ -1552,13 +1720,16 @@
 static stbi__uint32 stbi__get32le(stbi__context *s)
 {
    stbi__uint32 z = stbi__get16le(s);
-   return z + (stbi__get16le(s) << 16);
+   z += (stbi__uint32)stbi__get16le(s) << 16;
+   return z;
 }
 #endif
 
 #define STBI__BYTECAST(x)  ((stbi_uc) ((x) & 255))  // truncate int to byte without warnings
 
-
+#if defined(STBI_NO_JPEG) && defined(STBI_NO_PNG) && defined(STBI_NO_BMP) && defined(STBI_NO_PSD) && defined(STBI_NO_TGA) && defined(STBI_NO_GIF) && defined(STBI_NO_PIC) && defined(STBI_NO_PNM)
+// nothing
+#else
 //////////////////////////////////////////////////////////////////////////////
 //
 //  generic converter from built-in img_n to req_comp
@@ -1574,7 +1745,11 @@
 {
    return (stbi_uc) (((r*77) + (g*150) +  (29*b)) >> 8);
 }
+#endif
 
+#if defined(STBI_NO_PNG) && defined(STBI_NO_BMP) && defined(STBI_NO_PSD) && defined(STBI_NO_TGA) && defined(STBI_NO_GIF) && defined(STBI_NO_PIC) && defined(STBI_NO_PNM)
+// nothing
+#else
 static unsigned char *stbi__convert_format(unsigned char *data, int img_n, int req_comp, unsigned int x, unsigned int y)
 {
    int i,j;
@@ -1610,7 +1785,7 @@
          STBI__CASE(4,1) { dest[0]=stbi__compute_y(src[0],src[1],src[2]);                   } break;
          STBI__CASE(4,2) { dest[0]=stbi__compute_y(src[0],src[1],src[2]); dest[1] = src[3]; } break;
          STBI__CASE(4,3) { dest[0]=src[0];dest[1]=src[1];dest[2]=src[2];                    } break;
-         default: STBI_ASSERT(0);
+         default: STBI_ASSERT(0); STBI_FREE(data); STBI_FREE(good); return stbi__errpuc("unsupported", "Unsupported format conversion");
       }
       #undef STBI__CASE
    }
@@ -1618,12 +1793,20 @@
    STBI_FREE(data);
    return good;
 }
+#endif
 
+#if defined(STBI_NO_PNG) && defined(STBI_NO_PSD)
+// nothing
+#else
 static stbi__uint16 stbi__compute_y_16(int r, int g, int b)
 {
    return (stbi__uint16) (((r*77) + (g*150) +  (29*b)) >> 8);
 }
+#endif
 
+#if defined(STBI_NO_PNG) && defined(STBI_NO_PSD)
+// nothing
+#else
 static stbi__uint16 *stbi__convert_format16(stbi__uint16 *data, int img_n, int req_comp, unsigned int x, unsigned int y)
 {
    int i,j;
@@ -1659,7 +1842,7 @@
          STBI__CASE(4,1) { dest[0]=stbi__compute_y_16(src[0],src[1],src[2]);                   } break;
          STBI__CASE(4,2) { dest[0]=stbi__compute_y_16(src[0],src[1],src[2]); dest[1] = src[3]; } break;
          STBI__CASE(4,3) { dest[0]=src[0];dest[1]=src[1];dest[2]=src[2];                       } break;
-         default: STBI_ASSERT(0);
+         default: STBI_ASSERT(0); STBI_FREE(data); STBI_FREE(good); return (stbi__uint16*) stbi__errpuc("unsupported", "Unsupported format conversion");
       }
       #undef STBI__CASE
    }
@@ -1667,6 +1850,7 @@
    STBI_FREE(data);
    return good;
 }
+#endif
 
 #ifndef STBI_NO_LINEAR
 static float   *stbi__ldr_to_hdr(stbi_uc *data, int x, int y, int comp)
@@ -1819,9 +2003,12 @@
    int i,j,k=0;
    unsigned int code;
    // build size list for each symbol (from JPEG spec)
-   for (i=0; i < 16; ++i)
-      for (j=0; j < count[i]; ++j)
+   for (i=0; i < 16; ++i) {
+      for (j=0; j < count[i]; ++j) {
          h->size[k++] = (stbi_uc) (i+1);
+         if(k >= 257) return stbi__err("bad size list","Corrupt JPEG");
+      }
+   }
    h->size[k] = 0;
 
    // compute actual symbols (from jpeg spec)
@@ -1946,6 +2133,8 @@
 
    // convert the huffman code to the symbol id
    c = ((j->code_buffer >> (32 - k)) & stbi__bmask[k]) + h->delta[k];
+   if(c < 0 || c >= 256) // symbol id out of bounds!
+       return -1;
    STBI_ASSERT((((j->code_buffer) >> (32 - h->size[c])) & stbi__bmask[h->size[c]]) == h->code[c]);
 
    // convert the id to a symbol
@@ -1964,14 +2153,14 @@
    unsigned int k;
    int sgn;
    if (j->code_bits < n) stbi__grow_buffer_unsafe(j);
+   if (j->code_bits < n) return 0; // ran out of bits from stream, return 0s intead of continuing
 
-   sgn = (stbi__int32)j->code_buffer >> 31; // sign bit is always in MSB
+   sgn = j->code_buffer >> 31; // sign bit always in MSB; 0 if MSB clear (positive), 1 if MSB set (negative)
    k = stbi_lrot(j->code_buffer, n);
-   STBI_ASSERT(n >= 0 && n < (int) (sizeof(stbi__bmask)/sizeof(*stbi__bmask)));
    j->code_buffer = k & ~stbi__bmask[n];
    k &= stbi__bmask[n];
    j->code_bits -= n;
-   return k + (stbi__jbias[n] & ~sgn);
+   return k + (stbi__jbias[n] & (sgn - 1));
 }
 
 // get some unsigned bits
@@ -1979,6 +2168,7 @@
 {
    unsigned int k;
    if (j->code_bits < n) stbi__grow_buffer_unsafe(j);
+   if (j->code_bits < n) return 0; // ran out of bits from stream, return 0s intead of continuing
    k = stbi_lrot(j->code_buffer, n);
    j->code_buffer = k & ~stbi__bmask[n];
    k &= stbi__bmask[n];
@@ -1990,6 +2180,7 @@
 {
    unsigned int k;
    if (j->code_bits < 1) stbi__grow_buffer_unsafe(j);
+   if (j->code_bits < 1) return 0; // ran out of bits from stream, return 0s intead of continuing
    k = j->code_buffer;
    j->code_buffer <<= 1;
    --j->code_bits;
@@ -2021,14 +2212,16 @@
 
    if (j->code_bits < 16) stbi__grow_buffer_unsafe(j);
    t = stbi__jpeg_huff_decode(j, hdc);
-   if (t < 0) return stbi__err("bad huffman code","Corrupt JPEG");
+   if (t < 0 || t > 15) return stbi__err("bad huffman code","Corrupt JPEG");
 
    // 0 all the ac values now so we can do it 32-bits at a time
    memset(data,0,64*sizeof(data[0]));
 
    diff = t ? stbi__extend_receive(j, t) : 0;
+   if (!stbi__addints_valid(j->img_comp[b].dc_pred, diff)) return stbi__err("bad delta","Corrupt JPEG");
    dc = j->img_comp[b].dc_pred + diff;
    j->img_comp[b].dc_pred = dc;
+   if ((dc > SHRT_MAX) || (dequant[0] > SHRT_MAX) || !stbi__mul2shorts_valid((short) dc, (short) dequant[0])) return stbi__err("can't merge dc and ac", "Corrupt JPEG");
    data[0] = (short) (dc * dequant[0]);
 
    // decode AC components, see JPEG spec
@@ -2042,6 +2235,7 @@
       if (r) { // fast-AC path
          k += (r >> 4) & 15; // run
          s = r & 15; // combined length
+         if (s > j->code_bits) return stbi__err("bad huffman code", "Combined length longer than code bits available");
          j->code_buffer <<= s;
          j->code_bits -= s;
          // decode into unzigzag'd location
@@ -2078,11 +2272,14 @@
       // first scan for DC coefficient, must be first
       memset(data,0,64*sizeof(data[0])); // 0 all the ac values now
       t = stbi__jpeg_huff_decode(j, hdc);
+      if (t < 0 || t > 15) return stbi__err("can't merge dc and ac", "Corrupt JPEG");
       diff = t ? stbi__extend_receive(j, t) : 0;
 
+      if (!stbi__addints_valid(j->img_comp[b].dc_pred, diff)) return stbi__err("bad delta", "Corrupt JPEG");
       dc = j->img_comp[b].dc_pred + diff;
       j->img_comp[b].dc_pred = dc;
-      data[0] = (short) (dc << j->succ_low);
+      if ((dc > SHRT_MAX) || !stbi__mul2shorts_valid((short) dc, 1 << j->succ_low)) return stbi__err("can't merge dc and ac", "Corrupt JPEG");
+      data[0] = (short) (dc * (1 << j->succ_low));
    } else {
       // refinement scan for DC coefficient
       if (stbi__jpeg_get_bit(j))
@@ -2116,10 +2313,11 @@
          if (r) { // fast-AC path
             k += (r >> 4) & 15; // run
             s = r & 15; // combined length
+            if (s > j->code_bits) return stbi__err("bad huffman code", "Combined length longer than code bits available");
             j->code_buffer <<= s;
             j->code_bits -= s;
             zig = stbi__jpeg_dezigzag[k++];
-            data[zig] = (short) ((r >> 8) << shift);
+            data[zig] = (short) ((r >> 8) * (1 << shift));
          } else {
             int rs = stbi__jpeg_huff_decode(j, hac);
             if (rs < 0) return stbi__err("bad huffman code","Corrupt JPEG");
@@ -2137,7 +2335,7 @@
             } else {
                k += r;
                zig = stbi__jpeg_dezigzag[k++];
-               data[zig] = (short) (stbi__extend_receive(j,s) << shift);
+               data[zig] = (short) (stbi__extend_receive(j,s) * (1 << shift));
             }
          }
       } while (k <= j->spec_end);
@@ -2936,6 +3134,7 @@
                sizes[i] = stbi__get8(z->s);
                n += sizes[i];
             }
+            if(n > 256) return stbi__err("bad DHT header","Corrupt JPEG"); // Loop over i < n would write past end of values!
             L -= 17;
             if (tc == 0) {
                if (!stbi__build_huffman(z->huff_dc+th, sizes)) return 0;
@@ -3068,6 +3267,8 @@
    p  = stbi__get8(s);            if (p != 8) return stbi__err("only 8-bit","JPEG format not supported: 8-bit only"); // JPEG baseline
    s->img_y = stbi__get16be(s);   if (s->img_y == 0) return stbi__err("no header height", "JPEG format not supported: delayed height"); // Legal, but we don't handle it--but neither does IJG
    s->img_x = stbi__get16be(s);   if (s->img_x == 0) return stbi__err("0 width","Corrupt JPEG"); // JPEG requires
+   if (s->img_y > STBI_MAX_DIMENSIONS) return stbi__err("too large","Very large image (corrupt?)");
+   if (s->img_x > STBI_MAX_DIMENSIONS) return stbi__err("too large","Very large image (corrupt?)");
    c = stbi__get8(s);
    if (c != 3 && c != 1 && c != 4) return stbi__err("bad component count","Corrupt JPEG");
    s->img_n = c;
@@ -3099,6 +3300,13 @@
       if (z->img_comp[i].v > v_max) v_max = z->img_comp[i].v;
    }
 
+   // check that plane subsampling factors are integer ratios; our resamplers can't deal with fractional ratios
+   // and I've never seen a non-corrupted JPEG file actually use them
+   for (i=0; i < s->img_n; ++i) {
+      if (h_max % z->img_comp[i].h != 0) return stbi__err("bad H","Corrupt JPEG");
+      if (v_max % z->img_comp[i].v != 0) return stbi__err("bad V","Corrupt JPEG");
+   }
+
    // compute interleaved mcu info
    z->img_h_max = h_max;
    z->img_v_max = v_max;
@@ -3176,6 +3384,28 @@
    return 1;
 }
 
+static stbi_uc stbi__skip_jpeg_junk_at_end(stbi__jpeg *j)
+{
+   // some JPEGs have junk at end, skip over it but if we find what looks
+   // like a valid marker, resume there
+   while (!stbi__at_eof(j->s)) {
+      stbi_uc x = stbi__get8(j->s);
+      while (x == 255) { // might be a marker
+         if (stbi__at_eof(j->s)) return STBI__MARKER_none;
+         x = stbi__get8(j->s);
+         if (x != 0x00 && x != 0xff) {
+            // not a stuffed zero or lead-in to another marker, looks
+            // like an actual marker, return it
+            return x;
+         }
+         // stuffed zero has x=0 now which ends the loop, meaning we go
+         // back to regular scan loop.
+         // repeated 0xff keeps trying to read the next byte of the marker.
+      }
+   }
+   return STBI__MARKER_none;
+}
+
 // decode image to YCbCr format
 static int stbi__decode_jpeg_image(stbi__jpeg *j)
 {
@@ -3192,25 +3422,22 @@
          if (!stbi__process_scan_header(j)) return 0;
          if (!stbi__parse_entropy_coded_data(j)) return 0;
          if (j->marker == STBI__MARKER_none ) {
-            // handle 0s at the end of image data from IP Kamera 9060
-            while (!stbi__at_eof(j->s)) {
-               int x = stbi__get8(j->s);
-               if (x == 255) {
-                  j->marker = stbi__get8(j->s);
-                  break;
-               }
-            }
+         j->marker = stbi__skip_jpeg_junk_at_end(j);
             // if we reach eof without hitting a marker, stbi__get_marker() below will fail and we'll eventually return 0
          }
+         m = stbi__get_marker(j);
+         if (STBI__RESTART(m))
+            m = stbi__get_marker(j);
       } else if (stbi__DNL(m)) {
          int Ld = stbi__get16be(j->s);
          stbi__uint32 NL = stbi__get16be(j->s);
          if (Ld != 4) return stbi__err("bad DNL len", "Corrupt JPEG");
          if (NL != j->s->img_y) return stbi__err("bad DNL height", "Corrupt JPEG");
+         m = stbi__get_marker(j);
       } else {
-         if (!stbi__process_marker(j, m)) return 0;
+         if (!stbi__process_marker(j, m)) return 1;
+         m = stbi__get_marker(j);
       }
-      m = stbi__get_marker(j);
    }
    if (j->progressive)
       stbi__jpeg_finish(j);
@@ -3654,12 +3881,16 @@
    else
       decode_n = z->s->img_n;
 
+   // nothing to do if no components requested; check this now to avoid
+   // accessing uninitialized coutput[0] later
+   if (decode_n <= 0) { stbi__cleanup_jpeg(z); return NULL; }
+
    // resample and color-convert
    {
       int k;
       unsigned int i,j;
       stbi_uc *output;
-      stbi_uc *coutput[4];
+      stbi_uc *coutput[4] = { NULL, NULL, NULL, NULL };
 
       stbi__resample res_comp[4];
 
@@ -3796,6 +4027,8 @@
 {
    unsigned char* result;
    stbi__jpeg* j = (stbi__jpeg*) stbi__malloc(sizeof(stbi__jpeg));
+   if (!j) return stbi__errpuc("outofmem", "Out of memory");
+   memset(j, 0, sizeof(stbi__jpeg));
    STBI_NOTUSED(ri);
    j->s = s;
    stbi__setup_jpeg(j);
@@ -3808,6 +4041,8 @@
 {
    int r;
    stbi__jpeg* j = (stbi__jpeg*)stbi__malloc(sizeof(stbi__jpeg));
+   if (!j) return stbi__err("outofmem", "Out of memory");
+   memset(j, 0, sizeof(stbi__jpeg));
    j->s = s;
    stbi__setup_jpeg(j);
    r = stbi__decode_jpeg_header(j, STBI__SCAN_type);
@@ -3832,6 +4067,8 @@
 {
    int result;
    stbi__jpeg* j = (stbi__jpeg*) (stbi__malloc(sizeof(stbi__jpeg)));
+   if (!j) return stbi__err("outofmem", "Out of memory");
+   memset(j, 0, sizeof(stbi__jpeg));
    j->s = s;
    result = stbi__jpeg_info_raw(j, x, y, comp);
    STBI_FREE(j);
@@ -3851,6 +4088,7 @@
 // fast-way is faster to check than jpeg huffman, but slow way is slower
 #define STBI__ZFAST_BITS  9 // accelerate all cases in default tables
 #define STBI__ZFAST_MASK  ((1 << STBI__ZFAST_BITS) - 1)
+#define STBI__ZNSYMS 288 // number of symbols in literal/length alphabet
 
 // zlib-style huffman encoding
 // (jpegs packs from left, zlib from right, so can't share code)
@@ -3860,8 +4098,8 @@
    stbi__uint16 firstcode[16];
    int maxcode[17];
    stbi__uint16 firstsymbol[16];
-   stbi_uc  size[288];
-   stbi__uint16 value[288];
+   stbi_uc  size[STBI__ZNSYMS];
+   stbi__uint16 value[STBI__ZNSYMS];
 } stbi__zhuffman;
 
 stbi_inline static int stbi__bitreverse16(int n)
@@ -3938,6 +4176,7 @@
 {
    stbi_uc *zbuffer, *zbuffer_end;
    int num_bits;
+   int hit_zeof_once;
    stbi__uint32 code_buffer;
 
    char *zout;
@@ -3948,16 +4187,23 @@
    stbi__zhuffman z_length, z_distance;
 } stbi__zbuf;
 
+stbi_inline static int stbi__zeof(stbi__zbuf *z)
+{
+   return (z->zbuffer >= z->zbuffer_end);
+}
+
 stbi_inline static stbi_uc stbi__zget8(stbi__zbuf *z)
 {
-   if (z->zbuffer >= z->zbuffer_end) return 0;
-   return *z->zbuffer++;
+   return stbi__zeof(z) ? 0 : *z->zbuffer++;
 }
 
 static void stbi__fill_bits(stbi__zbuf *z)
 {
    do {
-      STBI_ASSERT(z->code_buffer < (1U << z->num_bits));
+      if (z->code_buffer >= (1U << z->num_bits)) {
+        z->zbuffer = z->zbuffer_end;  /* treat this as EOF so we fail. */
+        return;
+      }
       z->code_buffer |= (unsigned int) stbi__zget8(z) << z->num_bits;
       z->num_bits += 8;
    } while (z->num_bits <= 24);
@@ -3982,10 +4228,11 @@
    for (s=STBI__ZFAST_BITS+1; ; ++s)
       if (k < z->maxcode[s])
          break;
-   if (s == 16) return -1; // invalid code!
+   if (s >= 16) return -1; // invalid code!
    // code size is s, so:
    b = (k >> (16-s)) - z->firstcode[s] + z->firstsymbol[s];
-   STBI_ASSERT(z->size[b] == s);
+   if (b >= STBI__ZNSYMS) return -1; // some data was corrupt somewhere!
+   if (z->size[b] != s) return -1;  // was originally an assert, but report failure instead.
    a->code_buffer >>= s;
    a->num_bits -= s;
    return z->value[b];
@@ -3994,7 +4241,23 @@
 stbi_inline static int stbi__zhuffman_decode(stbi__zbuf *a, stbi__zhuffman *z)
 {
    int b,s;
-   if (a->num_bits < 16) stbi__fill_bits(a);
+   if (a->num_bits < 16) {
+      if (stbi__zeof(a)) {
+         if (!a->hit_zeof_once) {
+            // This is the first time we hit eof, insert 16 extra padding btis
+            // to allow us to keep going; if we actually consume any of them
+            // though, that is invalid data. This is caught later.
+            a->hit_zeof_once = 1;
+            a->num_bits += 16; // add 16 implicit zero bits
+         } else {
+            // We already inserted our extra 16 padding bits and are again
+            // out, this stream is actually prematurely terminated.
+            return -1;
+         }
+      } else {
+         stbi__fill_bits(a);
+      }
+   }
    b = z->fast[a->code_buffer & STBI__ZFAST_MASK];
    if (b) {
       s = b >> 9;
@@ -4008,13 +4271,16 @@
 static int stbi__zexpand(stbi__zbuf *z, char *zout, int n)  // need to make room for n bytes
 {
    char *q;
-   int cur, limit, old_limit;
+   unsigned int cur, limit, old_limit;
    z->zout = zout;
    if (!z->z_expandable) return stbi__err("output buffer limit","Corrupt PNG");
-   cur   = (int) (z->zout     - z->zout_start);
-   limit = old_limit = (int) (z->zout_end - z->zout_start);
-   while (cur + n > limit)
+   cur   = (unsigned int) (z->zout - z->zout_start);
+   limit = old_limit = (unsigned) (z->zout_end - z->zout_start);
+   if (UINT_MAX - cur < (unsigned) n) return stbi__err("outofmem", "Out of memory");
+   while (cur + n > limit) {
+      if(limit > UINT_MAX / 2) return stbi__err("outofmem", "Out of memory");
       limit *= 2;
+   }
    q = (char *) STBI_REALLOC_SIZED(z->zout_start, old_limit, limit);
    STBI_NOTUSED(old_limit);
    if (q == NULL) return stbi__err("outofmem", "Out of memory");
@@ -4055,17 +4321,25 @@
          int len,dist;
          if (z == 256) {
             a->zout = zout;
+            if (a->hit_zeof_once && a->num_bits < 16) {
+               // The first time we hit zeof, we inserted 16 extra zero bits into our bit
+               // buffer so the decoder can just do its speculative decoding. But if we
+               // actually consumed any of those bits (which is the case when num_bits < 16),
+               // the stream actually read past the end so it is malformed.
+               return stbi__err("unexpected end","Corrupt PNG");
+            }
             return 1;
          }
+         if (z >= 286) return stbi__err("bad huffman code","Corrupt PNG"); // per DEFLATE, length codes 286 and 287 must not appear in compressed data
          z -= 257;
          len = stbi__zlength_base[z];
          if (stbi__zlength_extra[z]) len += stbi__zreceive(a, stbi__zlength_extra[z]);
          z = stbi__zhuffman_decode(a, &a->z_distance);
-         if (z < 0) return stbi__err("bad huffman code","Corrupt PNG");
+         if (z < 0 || z >= 30) return stbi__err("bad huffman code","Corrupt PNG"); // per DEFLATE, distance codes 30 and 31 must not appear in compressed data
          dist = stbi__zdist_base[z];
          if (stbi__zdist_extra[z]) dist += stbi__zreceive(a, stbi__zdist_extra[z]);
          if (zout - a->zout_start < dist) return stbi__err("bad dist","Corrupt PNG");
-         if (zout + len > a->zout_end) {
+         if (len > a->zout_end - zout) {
             if (!stbi__zexpand(a, zout, len)) return 0;
             zout = a->zout;
          }
@@ -4112,11 +4386,12 @@
             c = stbi__zreceive(a,2)+3;
             if (n == 0) return stbi__err("bad codelengths", "Corrupt PNG");
             fill = lencodes[n-1];
-         } else if (c == 17)
+         } else if (c == 17) {
             c = stbi__zreceive(a,3)+3;
-         else {
-            STBI_ASSERT(c == 18);
+         } else if (c == 18) {
             c = stbi__zreceive(a,7)+11;
+         } else {
+            return stbi__err("bad codelengths", "Corrupt PNG");
          }
          if (ntot - n < c) return stbi__err("bad codelengths", "Corrupt PNG");
          memset(lencodes+n, fill, c);
@@ -4142,7 +4417,7 @@
       a->code_buffer >>= 8;
       a->num_bits -= 8;
    }
-   STBI_ASSERT(a->num_bits == 0);
+   if (a->num_bits < 0) return stbi__err("zlib corrupt","Corrupt PNG");
    // now fill header the normal way
    while (k < 4)
       header[k++] = stbi__zget8(a);
@@ -4164,6 +4439,7 @@
    int cm    = cmf & 15;
    /* int cinfo = cmf >> 4; */
    int flg   = stbi__zget8(a);
+   if (stbi__zeof(a)) return stbi__err("bad zlib header","Corrupt PNG"); // zlib spec
    if ((cmf*256+flg) % 31 != 0) return stbi__err("bad zlib header","Corrupt PNG"); // zlib spec
    if (flg & 32) return stbi__err("no preset dict","Corrupt PNG"); // preset dictionary not allowed in png
    if (cm != 8) return stbi__err("bad compression","Corrupt PNG"); // DEFLATE required for png
@@ -4171,7 +4447,7 @@
    return 1;
 }
 
-static const stbi_uc stbi__zdefault_length[288] =
+static const stbi_uc stbi__zdefault_length[STBI__ZNSYMS] =
 {
    8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
    8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
@@ -4207,6 +4483,7 @@
       if (!stbi__parse_zlib_header(a)) return 0;
    a->num_bits = 0;
    a->code_buffer = 0;
+   a->hit_zeof_once = 0;
    do {
       final = stbi__zreceive(a,1);
       type = stbi__zreceive(a,2);
@@ -4217,7 +4494,7 @@
       } else {
          if (type == 1) {
             // use fixed code lengths
-            if (!stbi__zbuild_huffman(&a->z_length  , stbi__zdefault_length  , 288)) return 0;
+            if (!stbi__zbuild_huffman(&a->z_length  , stbi__zdefault_length  , STBI__ZNSYMS)) return 0;
             if (!stbi__zbuild_huffman(&a->z_distance, stbi__zdefault_distance,  32)) return 0;
          } else {
             if (!stbi__compute_huffman_codes(a)) return 0;
@@ -4425,7 +4702,7 @@
          return stbi__err("invalid filter","Corrupt PNG");
 
       if (depth < 8) {
-         STBI_ASSERT(img_width_bytes <= x);
+         if (img_width_bytes > x) return stbi__err("invalid width","Corrupt PNG");
          cur += x*out_n - img_width_bytes; // store output to the rightmost img_len bytes, so we can decode in place
          filter_bytes = 1;
          width = img_width_bytes;
@@ -4613,6 +4890,7 @@
 
    // de-interlacing
    final = (stbi_uc *) stbi__malloc_mad3(a->s->img_x, a->s->img_y, out_bytes, 0);
+   if (!final) return stbi__err("outofmem", "Out of memory");
    for (p=0; p < 7; ++p) {
       int xorig[] = { 0,4,0,2,0,1,0 };
       int yorig[] = { 0,0,4,0,2,0,1 };
@@ -4733,19 +5011,46 @@
    return 1;
 }
 
-static int stbi__unpremultiply_on_load = 0;
-static int stbi__de_iphone_flag = 0;
+static int stbi__unpremultiply_on_load_global = 0;
+static int stbi__de_iphone_flag_global = 0;
 
 STBIDEF void stbi_set_unpremultiply_on_load(int flag_true_if_should_unpremultiply)
 {
-   stbi__unpremultiply_on_load = flag_true_if_should_unpremultiply;
+   stbi__unpremultiply_on_load_global = flag_true_if_should_unpremultiply;
 }
 
 STBIDEF void stbi_convert_iphone_png_to_rgb(int flag_true_if_should_convert)
 {
-   stbi__de_iphone_flag = flag_true_if_should_convert;
+   stbi__de_iphone_flag_global = flag_true_if_should_convert;
 }
 
+#ifndef STBI_THREAD_LOCAL
+#define stbi__unpremultiply_on_load  stbi__unpremultiply_on_load_global
+#define stbi__de_iphone_flag  stbi__de_iphone_flag_global
+#else
+static STBI_THREAD_LOCAL int stbi__unpremultiply_on_load_local, stbi__unpremultiply_on_load_set;
+static STBI_THREAD_LOCAL int stbi__de_iphone_flag_local, stbi__de_iphone_flag_set;
+
+STBIDEF void stbi_set_unpremultiply_on_load_thread(int flag_true_if_should_unpremultiply)
+{
+   stbi__unpremultiply_on_load_local = flag_true_if_should_unpremultiply;
+   stbi__unpremultiply_on_load_set = 1;
+}
+
+STBIDEF void stbi_convert_iphone_png_to_rgb_thread(int flag_true_if_should_convert)
+{
+   stbi__de_iphone_flag_local = flag_true_if_should_convert;
+   stbi__de_iphone_flag_set = 1;
+}
+
+#define stbi__unpremultiply_on_load  (stbi__unpremultiply_on_load_set           \
+                                       ? stbi__unpremultiply_on_load_local      \
+                                       : stbi__unpremultiply_on_load_global)
+#define stbi__de_iphone_flag  (stbi__de_iphone_flag_set                         \
+                                ? stbi__de_iphone_flag_local                    \
+                                : stbi__de_iphone_flag_global)
+#endif // STBI_THREAD_LOCAL
+
 static void stbi__de_iphone(stbi__png *z)
 {
    stbi__context *s = z->s;
@@ -4820,8 +5125,10 @@
             if (!first) return stbi__err("multiple IHDR","Corrupt PNG");
             first = 0;
             if (c.length != 13) return stbi__err("bad IHDR len","Corrupt PNG");
-            s->img_x = stbi__get32be(s); if (s->img_x > (1 << 24)) return stbi__err("too large","Very large image (corrupt?)");
-            s->img_y = stbi__get32be(s); if (s->img_y > (1 << 24)) return stbi__err("too large","Very large image (corrupt?)");
+            s->img_x = stbi__get32be(s);
+            s->img_y = stbi__get32be(s);
+            if (s->img_y > STBI_MAX_DIMENSIONS) return stbi__err("too large","Very large image (corrupt?)");
+            if (s->img_x > STBI_MAX_DIMENSIONS) return stbi__err("too large","Very large image (corrupt?)");
             z->depth = stbi__get8(s);  if (z->depth != 1 && z->depth != 2 && z->depth != 4 && z->depth != 8 && z->depth != 16)  return stbi__err("1/2/4/8/16-bit only","PNG not supported: 1/2/4/8/16-bit only");
             color = stbi__get8(s);  if (color > 6)         return stbi__err("bad ctype","Corrupt PNG");
             if (color == 3 && z->depth == 16)                  return stbi__err("bad ctype","Corrupt PNG");
@@ -4833,14 +5140,13 @@
             if (!pal_img_n) {
                s->img_n = (color & 2 ? 3 : 1) + (color & 4 ? 1 : 0);
                if ((1 << 30) / s->img_x / s->img_n < s->img_y) return stbi__err("too large", "Image too large to decode");
-               if (scan == STBI__SCAN_header) return 1;
             } else {
                // if paletted, then pal_n is our final components, and
                // img_n is # components to decompress/filter.
                s->img_n = 1;
                if ((1 << 30) / s->img_x / 4 < s->img_y) return stbi__err("too large","Corrupt PNG");
-               // if SCAN_header, have to scan to see if we have a tRNS
             }
+            // even with SCAN_header, have to scan to see if we have a tRNS
             break;
          }
 
@@ -4872,6 +5178,8 @@
                if (!(s->img_n & 1)) return stbi__err("tRNS with alpha","Corrupt PNG");
                if (c.length != (stbi__uint32) s->img_n*2) return stbi__err("bad tRNS len","Corrupt PNG");
                has_trans = 1;
+               // non-paletted with tRNS = constant alpha. if header-scanning, we can stop now.
+               if (scan == STBI__SCAN_header) { ++s->img_n; return 1; }
                if (z->depth == 16) {
                   for (k = 0; k < s->img_n; ++k) tc16[k] = (stbi__uint16)stbi__get16be(s); // copy the values as-is
                } else {
@@ -4884,7 +5192,13 @@
          case STBI__PNG_TYPE('I','D','A','T'): {
             if (first) return stbi__err("first not IHDR", "Corrupt PNG");
             if (pal_img_n && !pal_len) return stbi__err("no PLTE","Corrupt PNG");
-            if (scan == STBI__SCAN_header) { s->img_n = pal_img_n; return 1; }
+            if (scan == STBI__SCAN_header) {
+               // header scan definitely stops at first IDAT
+               if (pal_img_n)
+                  s->img_n = pal_img_n;
+               return 1;
+            }
+            if (c.length > (1u << 30)) return stbi__err("IDAT size limit", "IDAT section larger than 2^30 bytes");
             if ((int)(ioff + c.length) < (int)ioff) return 0;
             if (ioff + c.length > idata_limit) {
                stbi__uint32 idata_limit_old = idata_limit;
@@ -4938,6 +5252,8 @@
                ++s->img_n;
             }
             STBI_FREE(z->expanded); z->expanded = NULL;
+            // end of PNG chunk, read and skip CRC
+            stbi__get32be(s);
             return 1;
          }
 
@@ -4968,10 +5284,12 @@
    void *result=NULL;
    if (req_comp < 0 || req_comp > 4) return stbi__errpuc("bad req_comp", "Internal error");
    if (stbi__parse_png_file(p, STBI__SCAN_load, req_comp)) {
-      if (p->depth < 8)
+      if (p->depth <= 8)
          ri->bits_per_channel = 8;
+      else if (p->depth == 16)
+         ri->bits_per_channel = 16;
       else
-         ri->bits_per_channel = p->depth;
+         return stbi__errpuc("bad bits_per_channel", "PNG not supported: unsupported color depth");
       result = p->out;
       p->out = NULL;
       if (req_comp && req_comp != p->s->img_out_n) {
@@ -5076,7 +5394,7 @@
    if (z >= 0x00100) { n +=  8; z >>=  8; }
    if (z >= 0x00010) { n +=  4; z >>=  4; }
    if (z >= 0x00004) { n +=  2; z >>=  2; }
-   if (z >= 0x00002) { n +=  1; z >>=  1; }
+   if (z >= 0x00002) { n +=  1;/* >>=  1;*/ }
    return n;
 }
 
@@ -5107,7 +5425,7 @@
       v <<= -shift;
    else
       v >>= shift;
-   STBI_ASSERT(v >= 0 && v < 256);
+   STBI_ASSERT(v < 256);
    v >>= (8-bits);
    STBI_ASSERT(bits >= 0 && bits <= 8);
    return (int) ((unsigned) v * mul_table[bits]) >> shift_table[bits];
@@ -5117,8 +5435,35 @@
 {
    int bpp, offset, hsz;
    unsigned int mr,mg,mb,ma, all_a;
+   int extra_read;
 } stbi__bmp_data;
 
+static int stbi__bmp_set_mask_defaults(stbi__bmp_data *info, int compress)
+{
+   // BI_BITFIELDS specifies masks explicitly, don't override
+   if (compress == 3)
+      return 1;
+
+   if (compress == 0) {
+      if (info->bpp == 16) {
+         info->mr = 31u << 10;
+         info->mg = 31u <<  5;
+         info->mb = 31u <<  0;
+      } else if (info->bpp == 32) {
+         info->mr = 0xffu << 16;
+         info->mg = 0xffu <<  8;
+         info->mb = 0xffu <<  0;
+         info->ma = 0xffu << 24;
+         info->all_a = 0; // if all_a is 0 at end, then we loaded alpha channel but it was all 0
+      } else {
+         // otherwise, use defaults, which is all-0
+         info->mr = info->mg = info->mb = info->ma = 0;
+      }
+      return 1;
+   }
+   return 0; // error
+}
+
 static void *stbi__bmp_parse_header(stbi__context *s, stbi__bmp_data *info)
 {
    int hsz;
@@ -5129,6 +5474,9 @@
    info->offset = stbi__get32le(s);
    info->hsz = hsz = stbi__get32le(s);
    info->mr = info->mg = info->mb = info->ma = 0;
+   info->extra_read = 14;
+
+   if (info->offset < 0) return stbi__errpuc("bad BMP", "bad BMP");
 
    if (hsz != 12 && hsz != 40 && hsz != 56 && hsz != 108 && hsz != 124) return stbi__errpuc("unknown BMP", "BMP type not supported: unknown");
    if (hsz == 12) {
@@ -5143,6 +5491,8 @@
    if (hsz != 12) {
       int compress = stbi__get32le(s);
       if (compress == 1 || compress == 2) return stbi__errpuc("BMP RLE", "BMP type not supported: RLE");
+      if (compress >= 4) return stbi__errpuc("BMP JPEG/PNG", "BMP type not supported: unsupported compression"); // this includes PNG/JPEG modes
+      if (compress == 3 && info->bpp != 16 && info->bpp != 32) return stbi__errpuc("bad BMP", "bad BMP"); // bitfields requires 16 or 32 bits/pixel
       stbi__get32le(s); // discard sizeof
       stbi__get32le(s); // discard hres
       stbi__get32le(s); // discard vres
@@ -5157,21 +5507,12 @@
          }
          if (info->bpp == 16 || info->bpp == 32) {
             if (compress == 0) {
-               if (info->bpp == 32) {
-                  info->mr = 0xffu << 16;
-                  info->mg = 0xffu <<  8;
-                  info->mb = 0xffu <<  0;
-                  info->ma = 0xffu << 24;
-                  info->all_a = 0; // if all_a is 0 at end, then we loaded alpha channel but it was all 0
-               } else {
-                  info->mr = 31u << 10;
-                  info->mg = 31u <<  5;
-                  info->mb = 31u <<  0;
-               }
+               stbi__bmp_set_mask_defaults(info, compress);
             } else if (compress == 3) {
                info->mr = stbi__get32le(s);
                info->mg = stbi__get32le(s);
                info->mb = stbi__get32le(s);
+               info->extra_read += 12;
                // not documented, but generated by photoshop and handled by mspaint
                if (info->mr == info->mg && info->mg == info->mb) {
                   // ?!?!?
@@ -5181,6 +5522,7 @@
                return stbi__errpuc("bad BMP", "bad BMP");
          }
       } else {
+         // V4/V5 header
          int i;
          if (hsz != 108 && hsz != 124)
             return stbi__errpuc("bad BMP", "bad BMP");
@@ -5188,6 +5530,8 @@
          info->mg = stbi__get32le(s);
          info->mb = stbi__get32le(s);
          info->ma = stbi__get32le(s);
+         if (compress != 3) // override mr/mg/mb unless in BI_BITFIELDS mode, as per docs
+            stbi__bmp_set_mask_defaults(info, compress);
          stbi__get32le(s); // discard color space
          for (i=0; i < 12; ++i)
             stbi__get32le(s); // discard color space parameters
@@ -5220,6 +5564,9 @@
    flip_vertically = ((int) s->img_y) > 0;
    s->img_y = abs((int) s->img_y);
 
+   if (s->img_y > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
+   if (s->img_x > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
+
    mr = info.mr;
    mg = info.mg;
    mb = info.mb;
@@ -5228,13 +5575,35 @@
 
    if (info.hsz == 12) {
       if (info.bpp < 24)
-         psize = (info.offset - 14 - 24) / 3;
+         psize = (info.offset - info.extra_read - 24) / 3;
    } else {
       if (info.bpp < 16)
-         psize = (info.offset - 14 - info.hsz) >> 2;
+         psize = (info.offset - info.extra_read - info.hsz) >> 2;
+   }
+   if (psize == 0) {
+      // accept some number of extra bytes after the header, but if the offset points either to before
+      // the header ends or implies a large amount of extra data, reject the file as malformed
+      int bytes_read_so_far = s->callback_already_read + (int)(s->img_buffer - s->img_buffer_original);
+      int header_limit = 1024; // max we actually read is below 256 bytes currently.
+      int extra_data_limit = 256*4; // what ordinarily goes here is a palette; 256 entries*4 bytes is its max size.
+      if (bytes_read_so_far <= 0 || bytes_read_so_far > header_limit) {
+         return stbi__errpuc("bad header", "Corrupt BMP");
+      }
+      // we established that bytes_read_so_far is positive and sensible.
+      // the first half of this test rejects offsets that are either too small positives, or
+      // negative, and guarantees that info.offset >= bytes_read_so_far > 0. this in turn
+      // ensures the number computed in the second half of the test can't overflow.
+      if (info.offset < bytes_read_so_far || info.offset - bytes_read_so_far > extra_data_limit) {
+         return stbi__errpuc("bad offset", "Corrupt BMP");
+      } else {
+         stbi__skip(s, info.offset - bytes_read_so_far);
+      }
    }
 
-   s->img_n = ma ? 4 : 3;
+   if (info.bpp == 24 && ma == 0xff000000)
+      s->img_n = 3;
+   else
+      s->img_n = ma ? 4 : 3;
    if (req_comp && req_comp >= 3) // we can directly decode 3 or 4
       target = req_comp;
    else
@@ -5256,7 +5625,7 @@
          if (info.hsz != 12) stbi__get8(s);
          pal[i][3] = 255;
       }
-      stbi__skip(s, info.offset - 14 - info.hsz - psize * (info.hsz == 12 ? 3 : 4));
+      stbi__skip(s, info.offset - info.extra_read - info.hsz - psize * (info.hsz == 12 ? 3 : 4));
       if (info.bpp == 1) width = (s->img_x + 7) >> 3;
       else if (info.bpp == 4) width = (s->img_x + 1) >> 1;
       else if (info.bpp == 8) width = s->img_x;
@@ -5305,7 +5674,7 @@
       int rshift=0,gshift=0,bshift=0,ashift=0,rcount=0,gcount=0,bcount=0,acount=0;
       int z = 0;
       int easy=0;
-      stbi__skip(s, info.offset - 14 - info.hsz);
+      stbi__skip(s, info.offset - info.extra_read - info.hsz);
       if (info.bpp == 24) width = 3 * s->img_x;
       else if (info.bpp == 16) width = 2*s->img_x;
       else /* bpp = 32 and pad = 0 */ width=0;
@@ -5323,6 +5692,7 @@
          gshift = stbi__high_bit(mg)-7; gcount = stbi__bitcount(mg);
          bshift = stbi__high_bit(mb)-7; bcount = stbi__bitcount(mb);
          ashift = stbi__high_bit(ma)-7; acount = stbi__bitcount(ma);
+         if (rcount > 8 || gcount > 8 || bcount > 8 || acount > 8) { STBI_FREE(out); return stbi__errpuc("bad masks", "Corrupt BMP"); }
       }
       for (j=0; j < (int) s->img_y; ++j) {
          if (easy) {
@@ -5544,6 +5914,11 @@
    int RLE_repeating = 0;
    int read_next_pixel = 1;
    STBI_NOTUSED(ri);
+   STBI_NOTUSED(tga_x_origin); // @TODO
+   STBI_NOTUSED(tga_y_origin); // @TODO
+
+   if (tga_height > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
+   if (tga_width > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
 
    //   do a tiny bit of precessing
    if ( tga_image_type >= 8 )
@@ -5584,6 +5959,11 @@
       //   do I need to load a palette?
       if ( tga_indexed)
       {
+         if (tga_palette_len == 0) {  /* you have to have at least one entry! */
+            STBI_FREE(tga_data);
+            return stbi__errpuc("bad palette", "Corrupt TGA");
+         }
+
          //   any data to skip? (offset usually = 0)
          stbi__skip(s, tga_palette_start );
          //   load the palette
@@ -5707,6 +6087,7 @@
    //   Microsoft's C compilers happy... [8^(
    tga_palette_start = tga_palette_len = tga_palette_bits =
          tga_x_origin = tga_y_origin = 0;
+   STBI_NOTUSED(tga_palette_start);
    //   OK, done
    return tga_data;
 }
@@ -5791,6 +6172,9 @@
    h = stbi__get32be(s);
    w = stbi__get32be(s);
 
+   if (h > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
+   if (w > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
+
    // Make sure the depth is 8 bits.
    bitdepth = stbi__get16be(s);
    if (bitdepth != 8 && bitdepth != 16)
@@ -6145,6 +6529,10 @@
 
    x = stbi__get16be(s);
    y = stbi__get16be(s);
+
+   if (y > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
+   if (x > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
+
    if (stbi__at_eof(s))  return stbi__errpuc("bad file","file too short (pic header)");
    if (!stbi__mad3sizes_valid(x, y, 4, 0)) return stbi__errpuc("too large", "PIC image too large to decode");
 
@@ -6154,11 +6542,12 @@
 
    // intermediate buffer is RGBA
    result = (stbi_uc *) stbi__malloc_mad3(x, y, 4, 0);
+   if (!result) return stbi__errpuc("outofmem", "Out of memory");
    memset(result, 0xff, x*y*4);
 
    if (!stbi__pic_load_core(s,x,y,comp, result)) {
       STBI_FREE(result);
-      result=0;
+      return 0;
    }
    *px = x;
    *py = y;
@@ -6192,7 +6581,7 @@
    int w,h;
    stbi_uc *out;                 // output buffer (always 4 components)
    stbi_uc *background;          // The current "background" as far as a gif is concerned
-   stbi_uc *history; 
+   stbi_uc *history;
    int flags, bgindex, ratio, transparent, eflags;
    stbi_uc  pal[256][4];
    stbi_uc lpal[256][4];
@@ -6253,6 +6642,9 @@
    g->ratio = stbi__get8(s);
    g->transparent = -1;
 
+   if (g->w > STBI_MAX_DIMENSIONS) return stbi__err("too large","Very large image (corrupt?)");
+   if (g->h > STBI_MAX_DIMENSIONS) return stbi__err("too large","Very large image (corrupt?)");
+
    if (comp != 0) *comp = 4;  // can't actually tell whether it's 3 or 4 until we parse the comments
 
    if (is_info) return 1;
@@ -6266,6 +6658,7 @@
 static int stbi__gif_info_raw(stbi__context *s, int *x, int *y, int *comp)
 {
    stbi__gif* g = (stbi__gif*) stbi__malloc(sizeof(stbi__gif));
+   if (!g) return stbi__err("outofmem", "Out of memory");
    if (!stbi__gif_header(s, g, comp, 1)) {
       STBI_FREE(g);
       stbi__rewind( s );
@@ -6280,7 +6673,7 @@
 static void stbi__out_gif_code(stbi__gif *g, stbi__uint16 code)
 {
    stbi_uc *p, *c;
-   int idx; 
+   int idx;
 
    // recurse to decode the prefixes, since the linked-list is backwards,
    // and working backwards through an interleaved image would be nasty
@@ -6289,12 +6682,12 @@
 
    if (g->cur_y >= g->max_y) return;
 
-   idx = g->cur_x + g->cur_y; 
+   idx = g->cur_x + g->cur_y;
    p = &g->out[idx];
-   g->history[idx / 4] = 1;  
+   g->history[idx / 4] = 1;
 
    c = &g->color_table[g->codes[code].suffix * 4];
-   if (c[3] > 128) { // don't render transparent pixels; 
+   if (c[3] > 128) { // don't render transparent pixels;
       p[0] = c[2];
       p[1] = c[1];
       p[2] = c[0];
@@ -6403,32 +6796,36 @@
 // two back is the image from two frames ago, used for a very specific disposal format
 static stbi_uc *stbi__gif_load_next(stbi__context *s, stbi__gif *g, int *comp, int req_comp, stbi_uc *two_back)
 {
-   int dispose; 
-   int first_frame; 
-   int pi; 
-   int pcount; 
+   int dispose;
+   int first_frame;
+   int pi;
+   int pcount;
    STBI_NOTUSED(req_comp);
 
    // on first frame, any non-written pixels get the background colour (non-transparent)
-   first_frame = 0; 
+   first_frame = 0;
    if (g->out == 0) {
-      if (!stbi__gif_header(s, g, comp,0))     return 0; // stbi__g_failure_reason set by stbi__gif_header
-      g->out = (stbi_uc *) stbi__malloc(4 * g->w * g->h);
-      g->background = (stbi_uc *) stbi__malloc(4 * g->w * g->h); 
-      g->history = (stbi_uc *) stbi__malloc(g->w * g->h); 
-      if (g->out == 0)                      return stbi__errpuc("outofmem", "Out of memory");
+      if (!stbi__gif_header(s, g, comp,0)) return 0; // stbi__g_failure_reason set by stbi__gif_header
+      if (!stbi__mad3sizes_valid(4, g->w, g->h, 0))
+         return stbi__errpuc("too large", "GIF image is too large");
+      pcount = g->w * g->h;
+      g->out = (stbi_uc *) stbi__malloc(4 * pcount);
+      g->background = (stbi_uc *) stbi__malloc(4 * pcount);
+      g->history = (stbi_uc *) stbi__malloc(pcount);
+      if (!g->out || !g->background || !g->history)
+         return stbi__errpuc("outofmem", "Out of memory");
 
-      // image is treated as "transparent" at the start - ie, nothing overwrites the current background; 
+      // image is treated as "transparent" at the start - ie, nothing overwrites the current background;
       // background colour is only used for pixels that are not rendered first frame, after that "background"
-      // color refers to the color that was there the previous frame. 
-      memset( g->out, 0x00, 4 * g->w * g->h ); 
-      memset( g->background, 0x00, 4 * g->w * g->h ); // state of the background (starts transparent)
-      memset( g->history, 0x00, g->w * g->h );        // pixels that were affected previous frame
-      first_frame = 1; 
+      // color refers to the color that was there the previous frame.
+      memset(g->out, 0x00, 4 * pcount);
+      memset(g->background, 0x00, 4 * pcount); // state of the background (starts transparent)
+      memset(g->history, 0x00, pcount);        // pixels that were affected previous frame
+      first_frame = 1;
    } else {
-      // second frame - how do we dispoase of the previous one?
-      dispose = (g->eflags & 0x1C) >> 2; 
-      pcount = g->w * g->h; 
+      // second frame - how do we dispose of the previous one?
+      dispose = (g->eflags & 0x1C) >> 2;
+      pcount = g->w * g->h;
 
       if ((dispose == 3) && (two_back == 0)) {
          dispose = 2; // if I don't have an image to revert back to, default to the old background
@@ -6437,32 +6834,32 @@
       if (dispose == 3) { // use previous graphic
          for (pi = 0; pi < pcount; ++pi) {
             if (g->history[pi]) {
-               memcpy( &g->out[pi * 4], &two_back[pi * 4], 4 ); 
+               memcpy( &g->out[pi * 4], &two_back[pi * 4], 4 );
             }
          }
-      } else if (dispose == 2) { 
-         // restore what was changed last frame to background before that frame; 
+      } else if (dispose == 2) {
+         // restore what was changed last frame to background before that frame;
          for (pi = 0; pi < pcount; ++pi) {
             if (g->history[pi]) {
-               memcpy( &g->out[pi * 4], &g->background[pi * 4], 4 ); 
+               memcpy( &g->out[pi * 4], &g->background[pi * 4], 4 );
             }
          }
       } else {
-         // This is a non-disposal case eithe way, so just 
+         // This is a non-disposal case eithe way, so just
          // leave the pixels as is, and they will become the new background
          // 1: do not dispose
          // 0:  not specified.
       }
 
-      // background is what out is after the undoing of the previou frame; 
-      memcpy( g->background, g->out, 4 * g->w * g->h ); 
+      // background is what out is after the undoing of the previou frame;
+      memcpy( g->background, g->out, 4 * g->w * g->h );
    }
 
-   // clear my history; 
+   // clear my history;
    memset( g->history, 0x00, g->w * g->h );        // pixels that were affected previous frame
 
    for (;;) {
-      int tag = stbi__get8(s); 
+      int tag = stbi__get8(s);
       switch (tag) {
          case 0x2C: /* Image Descriptor */
          {
@@ -6484,6 +6881,13 @@
             g->cur_x   = g->start_x;
             g->cur_y   = g->start_y;
 
+            // if the width of the specified rectangle is 0, that means
+            // we may not see *any* pixels or the image is malformed;
+            // to make sure this is caught, move the current y down to
+            // max_y (which is what out_gif_code checks).
+            if (w == 0)
+               g->cur_y = g->max_y;
+
             g->lflags = stbi__get8(s);
 
             if (g->lflags & 0x40) {
@@ -6500,19 +6904,19 @@
             } else if (g->flags & 0x80) {
                g->color_table = (stbi_uc *) g->pal;
             } else
-               return stbi__errpuc("missing color table", "Corrupt GIF");            
-            
-            o = stbi__process_gif_raster(s, g);
-            if (o == NULL) return NULL;
+               return stbi__errpuc("missing color table", "Corrupt GIF");
 
-            // if this was the first frame, 
-            pcount = g->w * g->h; 
+            o = stbi__process_gif_raster(s, g);
+            if (!o) return NULL;
+
+            // if this was the first frame,
+            pcount = g->w * g->h;
             if (first_frame && (g->bgindex > 0)) {
                // if first frame, any pixel not drawn to gets the background color
                for (pi = 0; pi < pcount; ++pi) {
                   if (g->history[pi] == 0) {
-                     g->pal[g->bgindex][3] = 255; // just in case it was made transparent, undo that; It will be reset next frame if need be; 
-                     memcpy( &g->out[pi * 4], &g->pal[g->bgindex], 4 ); 
+                     g->pal[g->bgindex][3] = 255; // just in case it was made transparent, undo that; It will be reset next frame if need be;
+                     memcpy( &g->out[pi * 4], &g->pal[g->bgindex], 4 );
                   }
                }
             }
@@ -6523,7 +6927,7 @@
          case 0x21: // Comment Extension.
          {
             int len;
-            int ext = stbi__get8(s); 
+            int ext = stbi__get8(s);
             if (ext == 0xF9) { // Graphic Control Extension.
                len = stbi__get8(s);
                if (len == 4) {
@@ -6532,23 +6936,23 @@
 
                   // unset old transparent
                   if (g->transparent >= 0) {
-                     g->pal[g->transparent][3] = 255; 
-                  } 
+                     g->pal[g->transparent][3] = 255;
+                  }
                   if (g->eflags & 0x01) {
                      g->transparent = stbi__get8(s);
                      if (g->transparent >= 0) {
-                        g->pal[g->transparent][3] = 0; 
+                        g->pal[g->transparent][3] = 0;
                      }
                   } else {
                      // don't need transparent
-                     stbi__skip(s, 1); 
-                     g->transparent = -1; 
+                     stbi__skip(s, 1);
+                     g->transparent = -1;
                   }
                } else {
                   stbi__skip(s, len);
                   break;
                }
-            } 
+            }
             while ((len = stbi__get8(s)) != 0) {
                stbi__skip(s, len);
             }
@@ -6564,18 +6968,35 @@
    }
 }
 
+static void *stbi__load_gif_main_outofmem(stbi__gif *g, stbi_uc *out, int **delays)
+{
+   STBI_FREE(g->out);
+   STBI_FREE(g->history);
+   STBI_FREE(g->background);
+
+   if (out) STBI_FREE(out);
+   if (delays && *delays) STBI_FREE(*delays);
+   return stbi__errpuc("outofmem", "Out of memory");
+}
+
 static void *stbi__load_gif_main(stbi__context *s, int **delays, int *x, int *y, int *z, int *comp, int req_comp)
 {
    if (stbi__gif_test(s)) {
-      int layers = 0; 
+      int layers = 0;
       stbi_uc *u = 0;
       stbi_uc *out = 0;
-      stbi_uc *two_back = 0; 
+      stbi_uc *two_back = 0;
       stbi__gif g;
-      int stride; 
+      int stride;
+      int out_size = 0;
+      int delays_size = 0;
+
+      STBI_NOTUSED(out_size);
+      STBI_NOTUSED(delays_size);
+
       memset(&g, 0, sizeof(g));
       if (delays) {
-         *delays = 0; 
+         *delays = 0;
       }
 
       do {
@@ -6585,44 +7006,61 @@
          if (u) {
             *x = g.w;
             *y = g.h;
-            ++layers; 
-            stride = g.w * g.h * 4; 
-         
+            ++layers;
+            stride = g.w * g.h * 4;
+
             if (out) {
-               out = (stbi_uc*) STBI_REALLOC( out, layers * stride ); 
+               void *tmp = (stbi_uc*) STBI_REALLOC_SIZED( out, out_size, layers * stride );
+               if (!tmp)
+                  return stbi__load_gif_main_outofmem(&g, out, delays);
+               else {
+                   out = (stbi_uc*) tmp;
+                   out_size = layers * stride;
+               }
+
                if (delays) {
-                  *delays = (int*) STBI_REALLOC( *delays, sizeof(int) * layers ); 
+                  int *new_delays = (int*) STBI_REALLOC_SIZED( *delays, delays_size, sizeof(int) * layers );
+                  if (!new_delays)
+                     return stbi__load_gif_main_outofmem(&g, out, delays);
+                  *delays = new_delays;
+                  delays_size = layers * sizeof(int);
                }
             } else {
-               out = (stbi_uc*)stbi__malloc( layers * stride ); 
+               out = (stbi_uc*)stbi__malloc( layers * stride );
+               if (!out)
+                  return stbi__load_gif_main_outofmem(&g, out, delays);
+               out_size = layers * stride;
                if (delays) {
-                  *delays = (int*) stbi__malloc( layers * sizeof(int) ); 
+                  *delays = (int*) stbi__malloc( layers * sizeof(int) );
+                  if (!*delays)
+                     return stbi__load_gif_main_outofmem(&g, out, delays);
+                  delays_size = layers * sizeof(int);
                }
             }
-            memcpy( out + ((layers - 1) * stride), u, stride ); 
+            memcpy( out + ((layers - 1) * stride), u, stride );
             if (layers >= 2) {
-               two_back = out - 2 * stride; 
+               two_back = out - 2 * stride;
             }
 
             if (delays) {
-               (*delays)[layers - 1U] = g.delay; 
+               (*delays)[layers - 1U] = g.delay;
             }
          }
-      } while (u != 0); 
+      } while (u != 0);
 
-      // free temp buffer; 
-      STBI_FREE(g.out); 
-      STBI_FREE(g.history); 
-      STBI_FREE(g.background); 
+      // free temp buffer;
+      STBI_FREE(g.out);
+      STBI_FREE(g.history);
+      STBI_FREE(g.background);
 
-      // do the final conversion after loading everything; 
+      // do the final conversion after loading everything;
       if (req_comp && req_comp != 4)
          out = stbi__convert_format(out, 4, req_comp, layers * g.w, g.h);
 
-      *z = layers; 
+      *z = layers;
       return out;
    } else {
-      return stbi__errpuc("not GIF", "Image was not as a gif type."); 
+      return stbi__errpuc("not GIF", "Image was not as a gif type.");
    }
 }
 
@@ -6640,14 +7078,17 @@
       *y = g.h;
 
       // moved conversion to after successful load so that the same
-      // can be done for multiple frames. 
+      // can be done for multiple frames.
       if (req_comp && req_comp != 4)
          u = stbi__convert_format(u, 4, req_comp, g.w, g.h);
+   } else if (g.out) {
+      // if there was an error and we allocated an image buffer, free it!
+      STBI_FREE(g.out);
    }
 
-   // free buffers needed for multiple frame loading; 
+   // free buffers needed for multiple frame loading;
    STBI_FREE(g.history);
-   STBI_FREE(g.background); 
+   STBI_FREE(g.background);
 
    return u;
 }
@@ -6772,6 +7213,9 @@
    token += 3;
    width = (int) strtol(token, NULL, 10);
 
+   if (height > STBI_MAX_DIMENSIONS) return stbi__errpf("too large","Very large image (corrupt?)");
+   if (width > STBI_MAX_DIMENSIONS) return stbi__errpf("too large","Very large image (corrupt?)");
+
    *x = width;
    *y = height;
 
@@ -6840,12 +7284,12 @@
                   // Run
                   value = stbi__get8(s);
                   count -= 128;
-                  if (count > nleft) { STBI_FREE(hdr_data); STBI_FREE(scanline); return stbi__errpf("corrupt", "bad RLE data in HDR"); }
+                  if ((count == 0) || (count > nleft)) { STBI_FREE(hdr_data); STBI_FREE(scanline); return stbi__errpf("corrupt", "bad RLE data in HDR"); }
                   for (z = 0; z < count; ++z)
                      scanline[i++ * 4 + k] = value;
                } else {
                   // Dump
-                  if (count > nleft) { STBI_FREE(hdr_data); STBI_FREE(scanline); return stbi__errpf("corrupt", "bad RLE data in HDR"); }
+                  if ((count == 0) || (count > nleft)) { STBI_FREE(hdr_data); STBI_FREE(scanline); return stbi__errpf("corrupt", "bad RLE data in HDR"); }
                   for (z = 0; z < count; ++z)
                      scanline[i++ * 4 + k] = stbi__get8(s);
                }
@@ -6914,12 +7358,18 @@
 
    info.all_a = 255;
    p = stbi__bmp_parse_header(s, &info);
-   stbi__rewind( s );
-   if (p == NULL)
+   if (p == NULL) {
+      stbi__rewind( s );
       return 0;
+   }
    if (x) *x = s->img_x;
    if (y) *y = s->img_y;
-   if (comp) *comp = info.ma ? 4 : 3;
+   if (comp) {
+      if (info.bpp == 24 && info.ma == 0xff000000)
+         *comp = 3;
+      else
+         *comp = info.ma ? 4 : 3;
+   }
    return 1;
 }
 #endif
@@ -6977,8 +7427,8 @@
        stbi__rewind( s );
        return 0;
    }
-   (void) stbi__get32be(s);
-   (void) stbi__get32be(s);
+   STBI_NOTUSED(stbi__get32be(s));
+   STBI_NOTUSED(stbi__get32be(s));
    depth = stbi__get16be(s);
    if (depth != 16) {
        stbi__rewind( s );
@@ -7057,7 +7507,6 @@
 // Known limitations:
 //    Does not support comments in the header section
 //    Does not support ASCII image data (formats P2 and P3)
-//    Does not support 16-bit-per-channel
 
 #ifndef STBI_NO_PNM
 
@@ -7078,22 +7527,33 @@
    stbi_uc *out;
    STBI_NOTUSED(ri);
 
-   if (!stbi__pnm_info(s, (int *)&s->img_x, (int *)&s->img_y, (int *)&s->img_n))
+   ri->bits_per_channel = stbi__pnm_info(s, (int *)&s->img_x, (int *)&s->img_y, (int *)&s->img_n);
+   if (ri->bits_per_channel == 0)
       return 0;
 
+   if (s->img_y > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
+   if (s->img_x > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
+
    *x = s->img_x;
    *y = s->img_y;
    if (comp) *comp = s->img_n;
 
-   if (!stbi__mad3sizes_valid(s->img_n, s->img_x, s->img_y, 0))
+   if (!stbi__mad4sizes_valid(s->img_n, s->img_x, s->img_y, ri->bits_per_channel / 8, 0))
       return stbi__errpuc("too large", "PNM too large");
 
-   out = (stbi_uc *) stbi__malloc_mad3(s->img_n, s->img_x, s->img_y, 0);
+   out = (stbi_uc *) stbi__malloc_mad4(s->img_n, s->img_x, s->img_y, ri->bits_per_channel / 8, 0);
    if (!out) return stbi__errpuc("outofmem", "Out of memory");
-   stbi__getn(s, out, s->img_n * s->img_x * s->img_y);
+   if (!stbi__getn(s, out, s->img_n * s->img_x * s->img_y * (ri->bits_per_channel / 8))) {
+      STBI_FREE(out);
+      return stbi__errpuc("bad PNM", "PNM file truncated");
+   }
 
    if (req_comp && req_comp != s->img_n) {
-      out = stbi__convert_format(out, s->img_n, req_comp, s->img_x, s->img_y);
+      if (ri->bits_per_channel == 16) {
+         out = (stbi_uc *) stbi__convert_format16((stbi__uint16 *) out, s->img_n, req_comp, s->img_x, s->img_y);
+      } else {
+         out = stbi__convert_format(out, s->img_n, req_comp, s->img_x, s->img_y);
+      }
       if (out == NULL) return out; // stbi__convert_format frees input on failure
    }
    return out;
@@ -7130,6 +7590,8 @@
    while (!stbi__at_eof(s) && stbi__pnm_isdigit(*c)) {
       value = value*10 + (*c - '0');
       *c = (char) stbi__get8(s);
+      if((value > 214748364) || (value == 214748364 && *c > '7'))
+          return stbi__err("integer parse overflow", "Parsing an integer in the PPM header overflowed a 32-bit int");
    }
 
    return value;
@@ -7160,17 +7622,29 @@
    stbi__pnm_skip_whitespace(s, &c);
 
    *x = stbi__pnm_getinteger(s, &c); // read width
+   if(*x == 0)
+       return stbi__err("invalid width", "PPM image header had zero or overflowing width");
    stbi__pnm_skip_whitespace(s, &c);
 
    *y = stbi__pnm_getinteger(s, &c); // read height
+   if (*y == 0)
+       return stbi__err("invalid width", "PPM image header had zero or overflowing width");
    stbi__pnm_skip_whitespace(s, &c);
 
    maxv = stbi__pnm_getinteger(s, &c);  // read max value
-
-   if (maxv > 255)
-      return stbi__err("max value > 255", "PPM image not 8-bit");
+   if (maxv > 65535)
+      return stbi__err("max value > 65535", "PPM image supports only 8-bit and 16-bit images");
+   else if (maxv > 255)
+      return 16;
    else
-      return 1;
+      return 8;
+}
+
+static int stbi__pnm_is16(stbi__context *s)
+{
+   if (stbi__pnm_info(s, NULL, NULL, NULL) == 16)
+	   return 1;
+   return 0;
 }
 #endif
 
@@ -7226,6 +7700,9 @@
    if (stbi__psd_is16(s))  return 1;
    #endif
 
+   #ifndef STBI_NO_PNM
+   if (stbi__pnm_is16(s))  return 1;
+   #endif
    return 0;
 }
 
@@ -7305,7 +7782,7 @@
 
 /*
    revision history:
-      2.20  (2019-02-07) support utf8 filenames in Windows; fix warnings and platform ifdefs 
+      2.20  (2019-02-07) support utf8 filenames in Windows; fix warnings and platform ifdefs
       2.19  (2018-02-11) fix warning
       2.18  (2018-01-30) fix warnings
       2.17  (2018-01-29) change sbti__shiftsigned to avoid clang -O2 bug
diff --git a/stb_image_write.h b/stb_image_write.h
index ebaa0c5..e4b32ed 100644
--- a/stb_image_write.h
+++ b/stb_image_write.h
@@ -1,4 +1,4 @@
-/* stb_image_write - v1.11 - public domain - http://nothings.org/stb/stb_image_write.h
+/* stb_image_write - v1.16 - public domain - http://nothings.org/stb
    writes out PNG/BMP/TGA/JPEG/HDR images to C stdio - Sean Barrett 2010-2015
                                      no warranty implied; use at your own risk
 
@@ -10,11 +10,6 @@
 
    Will probably not work correctly with strict-aliasing optimizations.
 
-   If using a modern Microsoft Compiler, non-safe versions of CRT calls may cause 
-   compilation warnings or even errors. To avoid this, also before #including,
-
-       #define STBI_MSC_SECURE_CRT
-
 ABOUT:
 
    This header file is a library for writing images to C stdio or a callback.
@@ -110,7 +105,7 @@
 
    TGA supports RLE or non-RLE compressed data. To use non-RLE-compressed
    data, set the global variable 'stbi_write_tga_with_rle' to 0.
-   
+
    JPEG does ignore alpha channels in input data; quality is between 1 and 100.
    Higher quality looks better but results in a bigger image.
    JPEG baseline (no JPEG progressive).
@@ -118,7 +113,7 @@
 CREDITS:
 
 
-   Sean Barrett           -    PNG/BMP/TGA 
+   Sean Barrett           -    PNG/BMP/TGA
    Baldur Karlsson        -    HDR
    Jean-Sebastien Guay    -    TGA monochrome
    Tim Kelsey             -    misc enhancements
@@ -145,6 +140,7 @@
       Ivan Tikhonov
       github:ignotion
       Adam Schackart
+      Andrew Kensler
 
 LICENSE
 
@@ -171,9 +167,9 @@
 #endif
 
 #ifndef STB_IMAGE_WRITE_STATIC  // C++ forbids static forward declarations
-extern int stbi_write_tga_with_rle;
-extern int stbi_write_png_compression_level;
-extern int stbi_write_force_png_filter;
+STBIWDEF int stbi_write_tga_with_rle;
+STBIWDEF int stbi_write_png_compression_level;
+STBIWDEF int stbi_write_force_png_filter;
 #endif
 
 #ifndef STBI_WRITE_NO_STDIO
@@ -183,7 +179,7 @@
 STBIWDEF int stbi_write_hdr(char const *filename, int w, int h, int comp, const float *data);
 STBIWDEF int stbi_write_jpg(char const *filename, int x, int y, int comp, const void  *data, int quality);
 
-#ifdef STBI_WINDOWS_UTF8
+#ifdef STBIW_WINDOWS_UTF8
 STBIWDEF int stbiw_convert_wchar_to_utf8(char *buffer, size_t bufferlen, const wchar_t* input);
 #endif
 #endif
@@ -252,17 +248,17 @@
 #define STBIW_UCHAR(x) (unsigned char) ((x) & 0xff)
 
 #ifdef STB_IMAGE_WRITE_STATIC
-static int stbi__flip_vertically_on_write=0;
 static int stbi_write_png_compression_level = 8;
 static int stbi_write_tga_with_rle = 1;
 static int stbi_write_force_png_filter = -1;
 #else
 int stbi_write_png_compression_level = 8;
-int stbi__flip_vertically_on_write=0;
 int stbi_write_tga_with_rle = 1;
 int stbi_write_force_png_filter = -1;
 #endif
 
+static int stbi__flip_vertically_on_write = 0;
+
 STBIWDEF void stbi_flip_vertically_on_write(int flag)
 {
    stbi__flip_vertically_on_write = flag;
@@ -272,6 +268,8 @@
 {
    stbi_write_func *func;
    void *context;
+   unsigned char buffer[64];
+   int buf_used;
 } stbi__write_context;
 
 // initialize a callback-based context
@@ -288,7 +286,7 @@
    fwrite(data,1,size,(FILE*) context);
 }
 
-#if defined(_MSC_VER) && defined(STBI_WINDOWS_UTF8)
+#if defined(_WIN32) && defined(STBIW_WINDOWS_UTF8)
 #ifdef __cplusplus
 #define STBIW_EXTERN extern "C"
 #else
@@ -299,25 +297,25 @@
 
 STBIWDEF int stbiw_convert_wchar_to_utf8(char *buffer, size_t bufferlen, const wchar_t* input)
 {
-	return WideCharToMultiByte(65001 /* UTF8 */, 0, input, -1, buffer, bufferlen, NULL, NULL);
+   return WideCharToMultiByte(65001 /* UTF8 */, 0, input, -1, buffer, (int) bufferlen, NULL, NULL);
 }
 #endif
 
 static FILE *stbiw__fopen(char const *filename, char const *mode)
 {
    FILE *f;
-#if defined(_MSC_VER) && defined(STBI_WINDOWS_UTF8)
+#if defined(_WIN32) && defined(STBIW_WINDOWS_UTF8)
    wchar_t wMode[64];
    wchar_t wFilename[1024];
-	if (0 == MultiByteToWideChar(65001 /* UTF8 */, 0, filename, -1, wFilename, sizeof(wFilename)))
-      return 0;
-	
-	if (0 == MultiByteToWideChar(65001 /* UTF8 */, 0, mode, -1, wMode, sizeof(wMode)))
+   if (0 == MultiByteToWideChar(65001 /* UTF8 */, 0, filename, -1, wFilename, sizeof(wFilename)/sizeof(*wFilename)))
       return 0;
 
-#if _MSC_VER >= 1400
-	if (0 != _wfopen_s(&f, wFilename, wMode))
-		f = 0;
+   if (0 == MultiByteToWideChar(65001 /* UTF8 */, 0, mode, -1, wMode, sizeof(wMode)/sizeof(*wMode)))
+      return 0;
+
+#if defined(_MSC_VER) && _MSC_VER >= 1400
+   if (0 != _wfopen_s(&f, wFilename, wMode))
+      f = 0;
 #else
    f = _wfopen(wFilename, wMode);
 #endif
@@ -385,16 +383,36 @@
    va_end(v);
 }
 
+static void stbiw__write_flush(stbi__write_context *s)
+{
+   if (s->buf_used) {
+      s->func(s->context, &s->buffer, s->buf_used);
+      s->buf_used = 0;
+   }
+}
+
 static void stbiw__putc(stbi__write_context *s, unsigned char c)
 {
    s->func(s->context, &c, 1);
 }
 
+static void stbiw__write1(stbi__write_context *s, unsigned char a)
+{
+   if ((size_t)s->buf_used + 1 > sizeof(s->buffer))
+      stbiw__write_flush(s);
+   s->buffer[s->buf_used++] = a;
+}
+
 static void stbiw__write3(stbi__write_context *s, unsigned char a, unsigned char b, unsigned char c)
 {
-   unsigned char arr[3];
-   arr[0] = a, arr[1] = b, arr[2] = c;
-   s->func(s->context, arr, 3);
+   int n;
+   if ((size_t)s->buf_used + 3 > sizeof(s->buffer))
+      stbiw__write_flush(s);
+   n = s->buf_used;
+   s->buf_used = n+3;
+   s->buffer[n+0] = a;
+   s->buffer[n+1] = b;
+   s->buffer[n+2] = c;
 }
 
 static void stbiw__write_pixel(stbi__write_context *s, int rgb_dir, int comp, int write_alpha, int expand_mono, unsigned char *d)
@@ -403,7 +421,7 @@
    int k;
 
    if (write_alpha < 0)
-      s->func(s->context, &d[comp - 1], 1);
+      stbiw__write1(s, d[comp - 1]);
 
    switch (comp) {
       case 2: // 2 pixels = mono + alpha, alpha is written separately, so same as 1-channel case
@@ -411,7 +429,7 @@
          if (expand_mono)
             stbiw__write3(s, d[0], d[0], d[0]); // monochrome bmp
          else
-            s->func(s->context, d, 1);  // monochrome TGA
+            stbiw__write1(s, d[0]);  // monochrome TGA
          break;
       case 4:
          if (!write_alpha) {
@@ -427,7 +445,7 @@
          break;
    }
    if (write_alpha > 0)
-      s->func(s->context, &d[comp - 1], 1);
+      stbiw__write1(s, d[comp - 1]);
 }
 
 static void stbiw__write_pixels(stbi__write_context *s, int rgb_dir, int vdir, int x, int y, int comp, void *data, int write_alpha, int scanline_pad, int expand_mono)
@@ -441,16 +459,18 @@
    if (stbi__flip_vertically_on_write)
       vdir *= -1;
 
-   if (vdir < 0)
-      j_end = -1, j = y-1;
-   else
-      j_end =  y, j = 0;
+   if (vdir < 0) {
+      j_end = -1; j = y-1;
+   } else {
+      j_end =  y; j = 0;
+   }
 
    for (; j != j_end; j += vdir) {
       for (i=0; i < x; ++i) {
          unsigned char *d = (unsigned char *) data + (j*x+i)*comp;
          stbiw__write_pixel(s, rgb_dir, comp, write_alpha, expand_mono, d);
       }
+      stbiw__write_flush(s);
       s->func(s->context, &zero, scanline_pad);
    }
 }
@@ -471,16 +491,27 @@
 
 static int stbi_write_bmp_core(stbi__write_context *s, int x, int y, int comp, const void *data)
 {
-   int pad = (-x*3) & 3;
-   return stbiw__outfile(s,-1,-1,x,y,comp,1,(void *) data,0,pad,
-           "11 4 22 4" "4 44 22 444444",
-           'B', 'M', 14+40+(x*3+pad)*y, 0,0, 14+40,  // file header
-            40, x,y, 1,24, 0,0,0,0,0,0);             // bitmap header
+   if (comp != 4) {
+      // write RGB bitmap
+      int pad = (-x*3) & 3;
+      return stbiw__outfile(s,-1,-1,x,y,comp,1,(void *) data,0,pad,
+              "11 4 22 4" "4 44 22 444444",
+              'B', 'M', 14+40+(x*3+pad)*y, 0,0, 14+40,  // file header
+               40, x,y, 1,24, 0,0,0,0,0,0);             // bitmap header
+   } else {
+      // RGBA bitmaps need a v4 header
+      // use BI_BITFIELDS mode with 32bpp and alpha mask
+      // (straight BI_RGB with alpha mask doesn't work in most readers)
+      return stbiw__outfile(s,-1,-1,x,y,comp,1,(void *)data,1,0,
+         "11 4 22 4" "4 44 22 444444 4444 4 444 444 444 444",
+         'B', 'M', 14+108+x*y*4, 0, 0, 14+108, // file header
+         108, x,y, 1,32, 3,0,0,0,0,0, 0xff0000,0xff00,0xff,0xff000000u, 0, 0,0,0, 0,0,0, 0,0,0, 0,0,0); // bitmap V4 header
+   }
 }
 
 STBIWDEF int stbi_write_bmp_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data)
 {
-   stbi__write_context s;
+   stbi__write_context s = { 0 };
    stbi__start_write_callbacks(&s, func, context);
    return stbi_write_bmp_core(&s, x, y, comp, data);
 }
@@ -488,7 +519,7 @@
 #ifndef STBI_WRITE_NO_STDIO
 STBIWDEF int stbi_write_bmp(char const *filename, int x, int y, int comp, const void *data)
 {
-   stbi__write_context s;
+   stbi__write_context s = { 0 };
    if (stbi__start_write_file(&s,filename)) {
       int r = stbi_write_bmp_core(&s, x, y, comp, data);
       stbi__end_write_file(&s);
@@ -561,24 +592,25 @@
 
             if (diff) {
                unsigned char header = STBIW_UCHAR(len - 1);
-               s->func(s->context, &header, 1);
+               stbiw__write1(s, header);
                for (k = 0; k < len; ++k) {
                   stbiw__write_pixel(s, -1, comp, has_alpha, 0, begin + k * comp);
                }
             } else {
                unsigned char header = STBIW_UCHAR(len - 129);
-               s->func(s->context, &header, 1);
+               stbiw__write1(s, header);
                stbiw__write_pixel(s, -1, comp, has_alpha, 0, begin);
             }
          }
       }
+      stbiw__write_flush(s);
    }
    return 1;
 }
 
 STBIWDEF int stbi_write_tga_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data)
 {
-   stbi__write_context s;
+   stbi__write_context s = { 0 };
    stbi__start_write_callbacks(&s, func, context);
    return stbi_write_tga_core(&s, x, y, comp, (void *) data);
 }
@@ -586,7 +618,7 @@
 #ifndef STBI_WRITE_NO_STDIO
 STBIWDEF int stbi_write_tga(char const *filename, int x, int y, int comp, const void *data)
 {
-   stbi__write_context s;
+   stbi__write_context s = { 0 };
    if (stbi__start_write_file(&s,filename)) {
       int r = stbi_write_tga_core(&s, x, y, comp, (void *) data);
       stbi__end_write_file(&s);
@@ -602,6 +634,8 @@
 
 #define stbiw__max(a, b)  ((a) > (b) ? (a) : (b))
 
+#ifndef STBI_WRITE_NO_STDIO
+
 static void stbiw__linear_to_rgbe(unsigned char *rgbe, float *linear)
 {
    int exponent;
@@ -736,8 +770,8 @@
       char header[] = "#?RADIANCE\n# Written by stb_image_write.h\nFORMAT=32-bit_rle_rgbe\n";
       s->func(s->context, header, sizeof(header)-1);
 
-#ifdef STBI_MSC_SECURE_CRT
-      len = sprintf_s(buffer, "EXPOSURE=          1.0000000000000\n\n-Y %d +X %d\n", y, x);
+#ifdef __STDC_LIB_EXT1__
+      len = sprintf_s(buffer, sizeof(buffer), "EXPOSURE=          1.0000000000000\n\n-Y %d +X %d\n", y, x);
 #else
       len = sprintf(buffer, "EXPOSURE=          1.0000000000000\n\n-Y %d +X %d\n", y, x);
 #endif
@@ -752,15 +786,14 @@
 
 STBIWDEF int stbi_write_hdr_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const float *data)
 {
-   stbi__write_context s;
+   stbi__write_context s = { 0 };
    stbi__start_write_callbacks(&s, func, context);
    return stbi_write_hdr_core(&s, x, y, comp, (float *) data);
 }
 
-#ifndef STBI_WRITE_NO_STDIO
 STBIWDEF int stbi_write_hdr(char const *filename, int x, int y, int comp, const float *data)
 {
-   stbi__write_context s;
+   stbi__write_context s = { 0 };
    if (stbi__start_write_file(&s,filename)) {
       int r = stbi_write_hdr_core(&s, x, y, comp, (float *) data);
       stbi__end_write_file(&s);
@@ -778,7 +811,7 @@
 
 #ifndef STBIW_ZLIB_COMPRESS
 // stretchy buffer; stbiw__sbpush() == vector<>::push_back() -- stbiw__sbcount() == vector<>::size()
-#define stbiw__sbraw(a) ((int *) (a) - 2)
+#define stbiw__sbraw(a) ((int *) (void *) (a) - 2)
 #define stbiw__sbm(a)   stbiw__sbraw(a)[0]
 #define stbiw__sbn(a)   stbiw__sbraw(a)[1]
 
@@ -872,7 +905,7 @@
    unsigned int bitbuf=0;
    int i,j, bitcount=0;
    unsigned char *out = NULL;
-   unsigned char ***hash_table = (unsigned char***) STBIW_MALLOC(stbiw__ZHASH * sizeof(char**));
+   unsigned char ***hash_table = (unsigned char***) STBIW_MALLOC(stbiw__ZHASH * sizeof(unsigned char**));
    if (hash_table == NULL)
       return NULL;
    if (quality < 5) quality = 5;
@@ -895,7 +928,7 @@
       for (j=0; j < n; ++j) {
          if (hlist[j]-data > i-32768) { // if entry lies within window
             int d = stbiw__zlib_countm(hlist[j], data+i, data_len-i);
-            if (d >= best) best=d,bestloc=hlist[j];
+            if (d >= best) { best=d; bestloc=hlist[j]; }
          }
       }
       // when hash table entry is too long, delete half the entries
@@ -948,14 +981,31 @@
       (void) stbiw__sbfree(hash_table[i]);
    STBIW_FREE(hash_table);
 
+   // store uncompressed instead if compression was worse
+   if (stbiw__sbn(out) > data_len + 2 + ((data_len+32766)/32767)*5) {
+      stbiw__sbn(out) = 2;  // truncate to DEFLATE 32K window and FLEVEL = 1
+      for (j = 0; j < data_len;) {
+         int blocklen = data_len - j;
+         if (blocklen > 32767) blocklen = 32767;
+         stbiw__sbpush(out, data_len - j == blocklen); // BFINAL = ?, BTYPE = 0 -- no compression
+         stbiw__sbpush(out, STBIW_UCHAR(blocklen)); // LEN
+         stbiw__sbpush(out, STBIW_UCHAR(blocklen >> 8));
+         stbiw__sbpush(out, STBIW_UCHAR(~blocklen)); // NLEN
+         stbiw__sbpush(out, STBIW_UCHAR(~blocklen >> 8));
+         memcpy(out+stbiw__sbn(out), data+j, blocklen);
+         stbiw__sbn(out) += blocklen;
+         j += blocklen;
+      }
+   }
+
    {
       // compute adler32 on input
       unsigned int s1=1, s2=0;
       int blocklen = (int) (data_len % 5552);
       j=0;
       while (j < data_len) {
-         for (i=0; i < blocklen; ++i) s1 += data[j+i], s2 += s1;
-         s1 %= 65521, s2 %= 65521;
+         for (i=0; i < blocklen; ++i) { s1 += data[j+i]; s2 += s1; }
+         s1 %= 65521; s2 %= 65521;
          j += blocklen;
          blocklen = 5552;
       }
@@ -1048,13 +1098,13 @@
    int type = mymap[filter_type];
    unsigned char *z = pixels + stride_bytes * (stbi__flip_vertically_on_write ? height-1-y : y);
    int signed_stride = stbi__flip_vertically_on_write ? -stride_bytes : stride_bytes;
-    
+
    if (type==0) {
       memcpy(line_buffer, z, width*n);
       return;
    }
 
-   // first loop isn't optimized since it's just one pixel    
+   // first loop isn't optimized since it's just one pixel
    for (i = 0; i < n; ++i) {
       switch (type) {
          case 1: line_buffer[i] = z[i]; break;
@@ -1275,26 +1325,31 @@
    bits[0] = val & ((1<<bits[1])-1);
 }
 
-static int stbiw__jpg_processDU(stbi__write_context *s, int *bitBuf, int *bitCnt, float *CDU, float *fdtbl, int DC, const unsigned short HTDC[256][2], const unsigned short HTAC[256][2]) {
+static int stbiw__jpg_processDU(stbi__write_context *s, int *bitBuf, int *bitCnt, float *CDU, int du_stride, float *fdtbl, int DC, const unsigned short HTDC[256][2], const unsigned short HTAC[256][2]) {
    const unsigned short EOB[2] = { HTAC[0x00][0], HTAC[0x00][1] };
    const unsigned short M16zeroes[2] = { HTAC[0xF0][0], HTAC[0xF0][1] };
-   int dataOff, i, diff, end0pos;
+   int dataOff, i, j, n, diff, end0pos, x, y;
    int DU[64];
 
    // DCT rows
-   for(dataOff=0; dataOff<64; dataOff+=8) {
+   for(dataOff=0, n=du_stride*8; dataOff<n; dataOff+=du_stride) {
       stbiw__jpg_DCT(&CDU[dataOff], &CDU[dataOff+1], &CDU[dataOff+2], &CDU[dataOff+3], &CDU[dataOff+4], &CDU[dataOff+5], &CDU[dataOff+6], &CDU[dataOff+7]);
    }
    // DCT columns
    for(dataOff=0; dataOff<8; ++dataOff) {
-      stbiw__jpg_DCT(&CDU[dataOff], &CDU[dataOff+8], &CDU[dataOff+16], &CDU[dataOff+24], &CDU[dataOff+32], &CDU[dataOff+40], &CDU[dataOff+48], &CDU[dataOff+56]);
+      stbiw__jpg_DCT(&CDU[dataOff], &CDU[dataOff+du_stride], &CDU[dataOff+du_stride*2], &CDU[dataOff+du_stride*3], &CDU[dataOff+du_stride*4],
+                     &CDU[dataOff+du_stride*5], &CDU[dataOff+du_stride*6], &CDU[dataOff+du_stride*7]);
    }
    // Quantize/descale/zigzag the coefficients
-   for(i=0; i<64; ++i) {
-      float v = CDU[i]*fdtbl[i];
-      // DU[stbiw__jpg_ZigZag[i]] = (int)(v < 0 ? ceilf(v - 0.5f) : floorf(v + 0.5f));
-      // ceilf() and floorf() are C99, not C89, but I /think/ they're not needed here anyway?
-      DU[stbiw__jpg_ZigZag[i]] = (int)(v < 0 ? v - 0.5f : v + 0.5f);
+   for(y = 0, j=0; y < 8; ++y) {
+      for(x = 0; x < 8; ++x,++j) {
+         float v;
+         i = y*du_stride+x;
+         v = CDU[i]*fdtbl[j];
+         // DU[stbiw__jpg_ZigZag[j]] = (int)(v < 0 ? ceilf(v - 0.5f) : floorf(v + 0.5f));
+         // ceilf() and floorf() are C99, not C89, but I /think/ they're not needed here anyway?
+         DU[stbiw__jpg_ZigZag[j]] = (int)(v < 0 ? v - 0.5f : v + 0.5f);
+      }
    }
 
    // Encode DC
@@ -1409,10 +1464,10 @@
                              37,56,68,109,103,77,24,35,55,64,81,104,113,92,49,64,78,87,103,121,120,101,72,92,95,98,112,100,103,99};
    static const int UVQT[] = {17,18,24,47,99,99,99,99,18,21,26,66,99,99,99,99,24,26,56,99,99,99,99,99,47,66,99,99,99,99,99,99,
                               99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99};
-   static const float aasf[] = { 1.0f * 2.828427125f, 1.387039845f * 2.828427125f, 1.306562965f * 2.828427125f, 1.175875602f * 2.828427125f, 
+   static const float aasf[] = { 1.0f * 2.828427125f, 1.387039845f * 2.828427125f, 1.306562965f * 2.828427125f, 1.175875602f * 2.828427125f,
                                  1.0f * 2.828427125f, 0.785694958f * 2.828427125f, 0.541196100f * 2.828427125f, 0.275899379f * 2.828427125f };
 
-   int row, col, i, k;
+   int row, col, i, k, subsample;
    float fdtbl_Y[64], fdtbl_UV[64];
    unsigned char YTable[64], UVTable[64];
 
@@ -1421,6 +1476,7 @@
    }
 
    quality = quality ? quality : 90;
+   subsample = quality <= 90 ? 1 : 0;
    quality = quality < 1 ? 1 : quality > 100 ? 100 : quality;
    quality = quality < 50 ? 5000 / quality : 200 - quality * 2;
 
@@ -1443,7 +1499,7 @@
       static const unsigned char head0[] = { 0xFF,0xD8,0xFF,0xE0,0,0x10,'J','F','I','F',0,1,1,0,0,1,0,1,0,0,0xFF,0xDB,0,0x84,0 };
       static const unsigned char head2[] = { 0xFF,0xDA,0,0xC,3,1,0,2,0x11,3,0x11,0,0x3F,0 };
       const unsigned char head1[] = { 0xFF,0xC0,0,0x11,8,(unsigned char)(height>>8),STBIW_UCHAR(height),(unsigned char)(width>>8),STBIW_UCHAR(width),
-                                      3,1,0x11,0,2,0x11,1,3,0x11,1,0xFF,0xC4,0x01,0xA2,0 };
+                                      3,1,(unsigned char)(subsample?0x22:0x11),0,2,0x11,1,3,0x11,1,0xFF,0xC4,0x01,0xA2,0 };
       s->func(s->context, (void*)head0, sizeof(head0));
       s->func(s->context, (void*)YTable, sizeof(YTable));
       stbiw__putc(s, 1);
@@ -1466,36 +1522,74 @@
    // Encode 8x8 macroblocks
    {
       static const unsigned short fillBits[] = {0x7F, 7};
-      const unsigned char *imageData = (const unsigned char *)data;
       int DCY=0, DCU=0, DCV=0;
       int bitBuf=0, bitCnt=0;
       // comp == 2 is grey+alpha (alpha is ignored)
       int ofsG = comp > 2 ? 1 : 0, ofsB = comp > 2 ? 2 : 0;
+      const unsigned char *dataR = (const unsigned char *)data;
+      const unsigned char *dataG = dataR + ofsG;
+      const unsigned char *dataB = dataR + ofsB;
       int x, y, pos;
-      for(y = 0; y < height; y += 8) {
-         for(x = 0; x < width; x += 8) {
-            float YDU[64], UDU[64], VDU[64];
-            for(row = y, pos = 0; row < y+8; ++row) {
-               // row >= height => use last input row
-               int clamped_row = (row < height) ? row : height - 1;
-               int base_p = (stbi__flip_vertically_on_write ? (height-1-clamped_row) : clamped_row)*width*comp;
-               for(col = x; col < x+8; ++col, ++pos) {
-                  float r, g, b;
-                  // if col >= width => use pixel from last input column
-                  int p = base_p + ((col < width) ? col : (width-1))*comp;
+      if(subsample) {
+         for(y = 0; y < height; y += 16) {
+            for(x = 0; x < width; x += 16) {
+               float Y[256], U[256], V[256];
+               for(row = y, pos = 0; row < y+16; ++row) {
+                  // row >= height => use last input row
+                  int clamped_row = (row < height) ? row : height - 1;
+                  int base_p = (stbi__flip_vertically_on_write ? (height-1-clamped_row) : clamped_row)*width*comp;
+                  for(col = x; col < x+16; ++col, ++pos) {
+                     // if col >= width => use pixel from last input column
+                     int p = base_p + ((col < width) ? col : (width-1))*comp;
+                     float r = dataR[p], g = dataG[p], b = dataB[p];
+                     Y[pos]= +0.29900f*r + 0.58700f*g + 0.11400f*b - 128;
+                     U[pos]= -0.16874f*r - 0.33126f*g + 0.50000f*b;
+                     V[pos]= +0.50000f*r - 0.41869f*g - 0.08131f*b;
+                  }
+               }
+               DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y+0,   16, fdtbl_Y, DCY, YDC_HT, YAC_HT);
+               DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y+8,   16, fdtbl_Y, DCY, YDC_HT, YAC_HT);
+               DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y+128, 16, fdtbl_Y, DCY, YDC_HT, YAC_HT);
+               DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y+136, 16, fdtbl_Y, DCY, YDC_HT, YAC_HT);
 
-                  r = imageData[p+0];
-                  g = imageData[p+ofsG];
-                  b = imageData[p+ofsB];
-                  YDU[pos]=+0.29900f*r+0.58700f*g+0.11400f*b-128;
-                  UDU[pos]=-0.16874f*r-0.33126f*g+0.50000f*b;
-                  VDU[pos]=+0.50000f*r-0.41869f*g-0.08131f*b;
+               // subsample U,V
+               {
+                  float subU[64], subV[64];
+                  int yy, xx;
+                  for(yy = 0, pos = 0; yy < 8; ++yy) {
+                     for(xx = 0; xx < 8; ++xx, ++pos) {
+                        int j = yy*32+xx*2;
+                        subU[pos] = (U[j+0] + U[j+1] + U[j+16] + U[j+17]) * 0.25f;
+                        subV[pos] = (V[j+0] + V[j+1] + V[j+16] + V[j+17]) * 0.25f;
+                     }
+                  }
+                  DCU = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, subU, 8, fdtbl_UV, DCU, UVDC_HT, UVAC_HT);
+                  DCV = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, subV, 8, fdtbl_UV, DCV, UVDC_HT, UVAC_HT);
                }
             }
+         }
+      } else {
+         for(y = 0; y < height; y += 8) {
+            for(x = 0; x < width; x += 8) {
+               float Y[64], U[64], V[64];
+               for(row = y, pos = 0; row < y+8; ++row) {
+                  // row >= height => use last input row
+                  int clamped_row = (row < height) ? row : height - 1;
+                  int base_p = (stbi__flip_vertically_on_write ? (height-1-clamped_row) : clamped_row)*width*comp;
+                  for(col = x; col < x+8; ++col, ++pos) {
+                     // if col >= width => use pixel from last input column
+                     int p = base_p + ((col < width) ? col : (width-1))*comp;
+                     float r = dataR[p], g = dataG[p], b = dataB[p];
+                     Y[pos]= +0.29900f*r + 0.58700f*g + 0.11400f*b - 128;
+                     U[pos]= -0.16874f*r - 0.33126f*g + 0.50000f*b;
+                     V[pos]= +0.50000f*r - 0.41869f*g - 0.08131f*b;
+                  }
+               }
 
-            DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, YDU, fdtbl_Y, DCY, YDC_HT, YAC_HT);
-            DCU = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, UDU, fdtbl_UV, DCU, UVDC_HT, UVAC_HT);
-            DCV = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, VDU, fdtbl_UV, DCV, UVDC_HT, UVAC_HT);
+               DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y, 8, fdtbl_Y,  DCY, YDC_HT, YAC_HT);
+               DCU = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, U, 8, fdtbl_UV, DCU, UVDC_HT, UVAC_HT);
+               DCV = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, V, 8, fdtbl_UV, DCV, UVDC_HT, UVAC_HT);
+            }
          }
       }
 
@@ -1512,7 +1606,7 @@
 
 STBIWDEF int stbi_write_jpg_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data, int quality)
 {
-   stbi__write_context s;
+   stbi__write_context s = { 0 };
    stbi__start_write_callbacks(&s, func, context);
    return stbi_write_jpg_core(&s, x, y, comp, (void *) data, quality);
 }
@@ -1521,7 +1615,7 @@
 #ifndef STBI_WRITE_NO_STDIO
 STBIWDEF int stbi_write_jpg(char const *filename, int x, int y, int comp, const void *data, int quality)
 {
-   stbi__write_context s;
+   stbi__write_context s = { 0 };
    if (stbi__start_write_file(&s,filename)) {
       int r = stbi_write_jpg_core(&s, x, y, comp, data, quality);
       stbi__end_write_file(&s);
@@ -1534,8 +1628,17 @@
 #endif // STB_IMAGE_WRITE_IMPLEMENTATION
 
 /* Revision history
+      1.16  (2021-07-11)
+             make Deflate code emit uncompressed blocks when it would otherwise expand
+             support writing BMPs with alpha channel
+      1.15  (2020-07-13) unknown
+      1.14  (2020-02-02) updated JPEG writer to downsample chroma channels
+      1.13
+      1.12
+      1.11  (2019-08-11)
+
       1.10  (2019-02-07)
-             support utf8 filenames in Windows; fix warnings and platform ifdefs 
+             support utf8 filenames in Windows; fix warnings and platform ifdefs
       1.09  (2018-02-11)
              fix typo in zlib quality API, improve STB_I_W_STATIC in C++
       1.08  (2018-01-29)
@@ -1566,7 +1669,7 @@
              add HDR output
              fix monochrome BMP
       0.95 (2014-08-17)
-		       add monochrome TGA output
+             add monochrome TGA output
       0.94 (2014-05-31)
              rename private functions to avoid conflicts with stb_image.h
       0.93 (2014-05-27)
@@ -1584,38 +1687,38 @@
 ------------------------------------------------------------------------------
 ALTERNATIVE A - MIT License
 Copyright (c) 2017 Sean Barrett
-Permission is hereby granted, free of charge, to any person obtaining a copy of 
-this software and associated documentation files (the "Software"), to deal in 
-the Software without restriction, including without limitation the rights to 
-use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies 
-of the Software, and to permit persons to whom the Software is furnished to do 
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
 so, subject to the following conditions:
-The above copyright notice and this permission notice shall be included in all 
+The above copyright notice and this permission notice shall be included in all
 copies or substantial portions of the Software.
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 ------------------------------------------------------------------------------
 ALTERNATIVE B - Public Domain (www.unlicense.org)
 This is free and unencumbered software released into the public domain.
-Anyone is free to copy, modify, publish, use, compile, sell, or distribute this 
-software, either in source code form or as a compiled binary, for any purpose, 
+Anyone is free to copy, modify, publish, use, compile, sell, or distribute this
+software, either in source code form or as a compiled binary, for any purpose,
 commercial or non-commercial, and by any means.
-In jurisdictions that recognize copyright laws, the author or authors of this 
-software dedicate any and all copyright interest in the software to the public 
-domain. We make this dedication for the benefit of the public at large and to 
-the detriment of our heirs and successors. We intend this dedication to be an 
-overt act of relinquishment in perpetuity of all present and future rights to 
+In jurisdictions that recognize copyright laws, the author or authors of this
+software dedicate any and all copyright interest in the software to the public
+domain. We make this dedication for the benefit of the public at large and to
+the detriment of our heirs and successors. We intend this dedication to be an
+overt act of relinquishment in perpetuity of all present and future rights to
 this software under copyright law.
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
-AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN 
-ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 ------------------------------------------------------------------------------
 */