diff --git a/thirdparty/README.md b/thirdparty/README.md
index 7ed9a11c759..b42cf7f02b3 100644
--- a/thirdparty/README.md
+++ b/thirdparty/README.md
@@ -84,7 +84,7 @@ Files extracted from upstream source:
 ## libpng
 
 - Upstream: http://libpng.org/pub/png/libpng.html
-- Version: 1.6.26
+- Version: 1.6.28
 - License: libpng/zlib
 
 Files extracted from upstream source:
diff --git a/thirdparty/libpng/png.c b/thirdparty/libpng/png.c
index 6d5633cc09f..78ce39f46d8 100644
--- a/thirdparty/libpng/png.c
+++ b/thirdparty/libpng/png.c
@@ -1,8 +1,8 @@
 
 /* png.c - location for general purpose libpng functions
  *
- * Last changed in libpng 1.6.26 [October 20, 2016]
- * Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.28 [January 5, 2017]
+ * Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
@@ -14,7 +14,7 @@
 #include "pngpriv.h"
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_6_26 Your_png_h_is_not_version_1_6_26;
+typedef png_libpng_version_1_6_28 Your_png_h_is_not_version_1_6_28;
 
 /* Tells libpng that we have already handled the first "num_bytes" bytes
  * of the PNG file signature.  If the PNG data is embedded into another
@@ -477,6 +477,7 @@ png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,
          png_free(png_ptr, info_ptr->text);
          info_ptr->text = NULL;
          info_ptr->num_text = 0;
+         info_ptr->max_text = 0;
       }
    }
 #endif
@@ -775,15 +776,15 @@ png_get_copyright(png_const_structrp png_ptr)
 #else
 #  ifdef __STDC__
    return PNG_STRING_NEWLINE \
-      "libpng version 1.6.26 - October 20, 2016" PNG_STRING_NEWLINE \
-      "Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson" \
+      "libpng version 1.6.28 - January 5, 2017" PNG_STRING_NEWLINE \
+      "Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson" \
       PNG_STRING_NEWLINE \
       "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
       "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
       PNG_STRING_NEWLINE;
 #  else
-   return "libpng version 1.6.26 - October 20, 2016\
-      Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson\
+   return "libpng version 1.6.28 - January 5, 2017\
+      Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson\
       Copyright (c) 1996-1997 Andreas Dilger\
       Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";
 #  endif
@@ -4259,11 +4260,11 @@ png_set_option(png_structrp png_ptr, int option, int onoff)
    if (png_ptr != NULL && option >= 0 && option < PNG_OPTION_NEXT &&
       (option & 1) == 0)
    {
-      int mask = 3 << option;
-      int setting = (2 + (onoff != 0)) << option;
-      int current = png_ptr->options;
+      png_uint_32 mask = 3 << option;
+      png_uint_32 setting = (2 + (onoff != 0)) << option;
+      png_uint_32 current = png_ptr->options;
 
-      png_ptr->options = (png_byte)(((current & ~mask) | setting) & 0xff);
+      png_ptr->options = (png_uint_32)(((current & ~mask) | setting) & 0xff);
 
       return (current & mask) >> option;
    }
diff --git a/thirdparty/libpng/png.h b/thirdparty/libpng/png.h
index f0944631e05..e4cf032816c 100644
--- a/thirdparty/libpng/png.h
+++ b/thirdparty/libpng/png.h
@@ -1,9 +1,9 @@
 
 /* png.h - header file for PNG reference library
  *
- * libpng version 1.6.26, October 20, 2016
+ * libpng version 1.6.28, January 5, 2017
  *
- * Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
@@ -12,7 +12,7 @@
  * Authors and maintainers:
  *   libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
  *   libpng versions 0.89, June 1996, through 0.96, May 1997: Andreas Dilger
- *   libpng versions 0.97, January 1998, through 1.6.26, October 20, 2016:
+ *   libpng versions 0.97, January 1998, through 1.6.28, January 5, 2017:
  *     Glenn Randers-Pehrson.
  *   See also "Contributing Authors", below.
  */
@@ -25,12 +25,8 @@
  *
  * This code is released under the libpng license.
  *
- * Some files in the "contrib" directory and some configure-generated
- * files that are distributed with libpng have other copyright owners and
- * are released under other open source licenses.
- *
- * libpng versions 1.0.7, July 1, 2000 through 1.6.26, October 20, 2016 are
- * Copyright (c) 2000-2002, 2004, 2006-2016 Glenn Randers-Pehrson, are
+ * libpng versions 1.0.7, July 1, 2000 through 1.6.28, January 5, 2017 are
+ * Copyright (c) 2000-2002, 2004, 2006-2017 Glenn Randers-Pehrson, are
  * derived from libpng-1.0.6, and are distributed according to the same
  * disclaimer and license as libpng-1.0.6 with the following individuals
  * added to the list of Contributing Authors:
@@ -52,10 +48,10 @@
  *    risk of satisfactory quality, performance, accuracy, and effort is with
  *    the user.
  *
- * Some files in the "contrib" directory have other copyright owners and
+ * Some files in the "contrib" directory and some configure-generated
+ * files that are distributed with libpng have other copyright owners and
  * are released under other open source licenses.
  *
- *
  * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
  * Copyright (c) 1998-2000 Glenn Randers-Pehrson, are derived from
  * libpng-0.96, and are distributed according to the same disclaimer and
@@ -66,9 +62,6 @@
  *    Glenn Randers-Pehrson
  *    Willem van Schaik
  *
- * Some files in the "scripts" directory have different copyright owners
- * but are also released under this license.
- *
  * libpng versions 0.89, June 1996, through 0.96, May 1997, are
  * Copyright (c) 1996-1997 Andreas Dilger, are derived from libpng-0.88,
  * and are distributed according to the same disclaimer and license as
@@ -214,11 +207,11 @@
  *    ...
  *    1.0.19                  10    10019  10.so.0.19[.0]
  *    ...
- *    1.2.56                  13    10256  12.so.0.56[.0]
+ *    1.2.57                  13    10257  12.so.0.57[.0]
  *    ...
- *    1.5.27                  15    10527  15.so.15.27[.0]
+ *    1.5.28                  15    10527  15.so.15.28[.0]
  *    ...
- *    1.6.26                  16    10626  16.so.16.26[.0]
+ *    1.6.28                  16    10628  16.so.16.28[.0]
  *
  *    Henceforth the source version will match the shared-library major
  *    and minor numbers; the shared-library major version number will be
@@ -246,13 +239,13 @@
  * Y2K compliance in libpng:
  * =========================
  *
- *    October 20, 2016
+ *    January 5, 2017
  *
  *    Since the PNG Development group is an ad-hoc body, we can't make
  *    an official declaration.
  *
  *    This is your unofficial assurance that libpng from version 0.71 and
- *    upward through 1.6.26 are Y2K compliant.  It is my belief that
+ *    upward through 1.6.28 are Y2K compliant.  It is my belief that
  *    earlier versions were also Y2K compliant.
  *
  *    Libpng only has two year fields.  One is a 2-byte unsigned integer
@@ -314,8 +307,8 @@
  */
 
 /* Version information for png.h - this should match the version in png.c */
-#define PNG_LIBPNG_VER_STRING "1.6.26"
-#define PNG_HEADER_VERSION_STRING " libpng version 1.6.26 - October 20, 2016\n"
+#define PNG_LIBPNG_VER_STRING "1.6.28"
+#define PNG_HEADER_VERSION_STRING " libpng version 1.6.28 - January 5, 2017\n"
 
 #define PNG_LIBPNG_VER_SONUM   16
 #define PNG_LIBPNG_VER_DLLNUM  16
@@ -323,7 +316,7 @@
 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
 #define PNG_LIBPNG_VER_MAJOR   1
 #define PNG_LIBPNG_VER_MINOR   6
-#define PNG_LIBPNG_VER_RELEASE 26
+#define PNG_LIBPNG_VER_RELEASE 28
 
 /* This should match the numeric part of the final component of
  * PNG_LIBPNG_VER_STRING, omitting any leading zero:
@@ -354,7 +347,7 @@
  * version 1.0.0 was mis-numbered 100 instead of 10000).  From
  * version 1.0.1 it's    xxyyzz, where x=major, y=minor, z=release
  */
-#define PNG_LIBPNG_VER 10626 /* 1.6.26 */
+#define PNG_LIBPNG_VER 10628 /* 1.6.28 */
 
 /* Library configuration: these options cannot be changed after
  * the library has been built.
@@ -464,7 +457,7 @@ extern "C" {
 /* This triggers a compiler error in png.c, if png.c and png.h
  * do not agree upon the version number.
  */
-typedef char* png_libpng_version_1_6_26;
+typedef char* png_libpng_version_1_6_28;
 
 /* Basic control structions.  Read libpng-manual.txt or libpng.3 for more info.
  *
@@ -3230,7 +3223,8 @@ PNG_EXPORT(245, int, png_image_write_to_memory, (png_imagep image, void *memory,
 #ifdef PNG_MIPS_MSA_API_SUPPORTED
 #  define PNG_MIPS_MSA   6 /* HARDWARE: MIPS Msa SIMD instructions supported */
 #endif
-#define PNG_OPTION_NEXT  8 /* Next option - numbers must be even */
+#define PNG_IGNORE_ADLER32 8
+#define PNG_OPTION_NEXT  10 /* Next option - numbers must be even */
 
 /* Return values: NOTE: there are four values and 'off' is *not* zero */
 #define PNG_OPTION_UNSET   0 /* Unset - defaults to off */
diff --git a/thirdparty/libpng/pngconf.h b/thirdparty/libpng/pngconf.h
index 5c891eb8b8c..5e8b40bcfb1 100644
--- a/thirdparty/libpng/pngconf.h
+++ b/thirdparty/libpng/pngconf.h
@@ -1,7 +1,7 @@
 
 /* pngconf.h - machine configurable file for libpng
  *
- * libpng version 1.6.26, October 20, 2016
+ * libpng version 1.6.28, January 5, 2017
  *
  * Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/thirdparty/libpng/pnglibconf.h b/thirdparty/libpng/pnglibconf.h
index ba7805ff599..ee705736056 100644
--- a/thirdparty/libpng/pnglibconf.h
+++ b/thirdparty/libpng/pnglibconf.h
@@ -1,8 +1,8 @@
-/* libpng 1.6.26 STANDARD API DEFINITION */
+/* libpng 1.6.28 STANDARD API DEFINITION */
 
 /* pnglibconf.h - library build configuration */
 
-/* Libpng version 1.6.26 - October 20, 2016 */
+/* Libpng version 1.6.28 - January 5, 2017 */
 
 /* Copyright (c) 1998-2015 Glenn Randers-Pehrson */
 
diff --git a/thirdparty/libpng/pngrutil.c b/thirdparty/libpng/pngrutil.c
index fb5f5f083de..bee0ea1158c 100644
--- a/thirdparty/libpng/pngrutil.c
+++ b/thirdparty/libpng/pngrutil.c
@@ -1,7 +1,7 @@
 
 /* pngrutil.c - utilities to read a PNG file
  *
- * Last changed in libpng 1.6.26 [October 20, 2016]
+ * Last changed in libpng 1.6.27 [January 5, 2017]
  * Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -418,9 +418,10 @@ png_inflate_claim(png_structrp png_ptr, png_uint_32 owner)
             png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED;
       }
 
-#if ZLIB_VERNUM >= 0x1281
-      /* Turn off validation of the ADLER32 checksum */
-      if ((png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) != 0)
+#if ZLIB_VERNUM >= 0x1281 && \
+   defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_IGNORE_ADLER32)
+      if (((png_ptr->options >> PNG_IGNORE_ADLER32) & 3) == PNG_OPTION_ON)
+         /* Turn off validation of the ADLER32 checksum in IDAT chunks */
          ret = inflateValidate(&png_ptr->zstream, 0);
 #endif
 
@@ -716,7 +717,7 @@ png_decompress_chunk(png_structrp png_ptr,
                    * the extra space may otherwise be used as a Trojan Horse.
                    */
                   if (ret == Z_STREAM_END &&
-                     chunklength - prefix_size != lzsize)
+                      chunklength - prefix_size != lzsize)
                      png_chunk_benign_error(png_ptr, "extra compressed data");
                }
 
@@ -826,7 +827,7 @@ png_inflate_read(png_structrp png_ptr, png_bytep read_buffer, uInt read_size,
       return Z_STREAM_ERROR;
    }
 }
-#endif
+#endif /* READ_iCCP */
 
 /* Read and check the IDHR chunk */
 
@@ -4107,15 +4108,7 @@ png_read_IDAT_data(png_structrp png_ptr, png_bytep output,
          png_zstream_error(png_ptr, ret);
 
          if (output != NULL)
-         {
-            if(!strncmp(png_ptr->zstream.msg,"incorrect data check",20))
-            {
-               png_chunk_benign_error(png_ptr, "ADLER32 checksum mismatch");
-               continue;
-            }
-            else
-               png_chunk_error(png_ptr, png_ptr->zstream.msg);
-         }
+            png_chunk_error(png_ptr, png_ptr->zstream.msg);
 
          else /* checking */
          {
diff --git a/thirdparty/libpng/pngstruct.h b/thirdparty/libpng/pngstruct.h
index 55516eaaa11..749d7e35b1c 100644
--- a/thirdparty/libpng/pngstruct.h
+++ b/thirdparty/libpng/pngstruct.h
@@ -1,8 +1,8 @@
 
 /* pngstruct.h - header file for PNG reference library
  *
- * Last changed in libpng 1.6.24 [August 4, 2016]
- * Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.28 [January 5, 2017]
+ * Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
@@ -353,7 +353,7 @@ struct png_struct_def
 
 /* Options */
 #ifdef PNG_SET_OPTION_SUPPORTED
-   png_byte options;           /* On/off state (up to 4 options) */
+   png_uint_32 options;           /* On/off state (up to 16 options) */
 #endif
 
 #if PNG_LIBPNG_VER < 10700