diff --git a/GRRLIB/lib/png/png.c b/GRRLIB/lib/png/png.c
index 4b02764..5074cfd 100644
--- a/GRRLIB/lib/png/png.c
+++ b/GRRLIB/lib/png/png.c
@@ -17,11 +17,7 @@
 #include "pngpriv.h"
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef version_1_4_4 Your_png_h_is_not_version_1_4_4;
-
-/* Version information for C files.  This had better match the version
- * string defined in png.h.
- */
+typedef version_1_4_5 Your_png_h_is_not_version_1_4_5;
 
 /* 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
@@ -551,13 +547,13 @@ png_get_copyright(png_structp png_ptr)
 #else
 #ifdef __STDC__
    return ((png_charp) PNG_STRING_NEWLINE \
-     "libpng version 1.4.4 - September 23, 2010" PNG_STRING_NEWLINE \
+     "libpng version 1.4.5 - December 9, 2010" PNG_STRING_NEWLINE \
      "Copyright (c) 1998-2010 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 ((png_charp) "libpng version 1.4.4 - September 23, 2010\
+      return ((png_charp) "libpng version 1.4.5 - December 9, 2010\
       Copyright (c) 1998-2010 Glenn Randers-Pehrson\
       Copyright (c) 1996-1997 Andreas Dilger\
       Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.");
@@ -678,7 +674,7 @@ png_convert_size(size_t size)
 */
 
 void /* PRIVATE */
-png_64bit_product (long v1, long v2, unsigned long *hi_product,
+png_64bit_product(long v1, long v2, unsigned long *hi_product,
    unsigned long *lo_product)
 {
    int a, b, c, d;
diff --git a/GRRLIB/lib/png/png.h b/GRRLIB/lib/png/png.h
index f46e97c..ee6876a 100644
--- a/GRRLIB/lib/png/png.h
+++ b/GRRLIB/lib/png/png.h
@@ -1,7 +1,7 @@
 
 /* png.h - header file for PNG reference library
  *
- * libpng version 1.4.4 - September 23, 2010
+ * libpng version 1.4.5 - December 9, 2010
  * Copyright (c) 1998-2010 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.)
@@ -11,7 +11,7 @@
  * Authors and maintainers:
  *  libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
  *  libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
- *  libpng versions 0.97, January 1998, through 1.4.4 - September 23, 2010: Glenn
+ *  libpng versions 0.97, January 1998, through 1.4.5 - December 9, 2010: Glenn
  *  See also "Contributing Authors", below.
  *
  * Note about libpng version numbers:
@@ -146,7 +146,13 @@
  *    1.4.3rc01-03            14    10403  14.so.14.3[.0]
  *    1.4.3                   14    10403  14.so.14.3[.0]
  *    1.4.4beta01-08          14    10404  14.so.14.4[.0]
- *    1.4.4rc01-06            14    10404  14.so.14.4[.0]
+ *    1.4.4rc01-05            14    10404  14.so.14.4[.0]
+ *    1.4.4                   14    10404  14.so.14.4[.0]
+ *    1.4.5beta01-04          14    10405  14.so.14.5[.0]
+ *    1.4.5rc01               14    10405  14.so.14.5[.0]
+ *    1.4.5beta05-07          14    10405  14.so.14.5[.0]
+ *    1.4.5rc02-03            14    10405  14.so.14.5[.0]
+ *    1.4.5                   14    10405  14.so.14.5[.0]
  *
  *    Henceforth the source version will match the shared-library major
  *    and minor numbers; the shared-library major version number will be
@@ -178,7 +184,7 @@
  *
  * This code is released under the libpng license.
  *
- * libpng versions 1.2.6, August 15, 2004, through 1.4.4, September 23, 2010, are
+ * libpng versions 1.2.6, August 15, 2004, through 1.4.5, December 9, 2010, are
  * Copyright (c) 2004, 2006-2010 Glenn Randers-Pehrson, and are
  * distributed according to the same disclaimer and license as libpng-1.2.5
  * with the following individual added to the list of Contributing Authors:
@@ -290,13 +296,13 @@
  * Y2K compliance in libpng:
  * =========================
  *
- *    September 23, 2010
+ *    December 9, 2010
  *
  *    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 1.4.4 are Y2K compliant.  It is my belief that earlier
+ *    upward through 1.4.5 are Y2K compliant.  It is my belief that earlier
  *    versions were also Y2K compliant.
  *
  *    Libpng only has three year fields.  One is a 2-byte unsigned integer
@@ -352,9 +358,9 @@
  */
 
 /* Version information for png.h - this should match the version in png.c */
-#define PNG_LIBPNG_VER_STRING "1.4.4"
+#define PNG_LIBPNG_VER_STRING "1.4.5"
 #define PNG_HEADER_VERSION_STRING \
-   " libpng version 1.4.4 - September 23, 2010\n"
+   " libpng version 1.4.5 - December 9, 2010\n"
 
 #define PNG_LIBPNG_VER_SONUM   14
 #define PNG_LIBPNG_VER_DLLNUM  14
@@ -362,7 +368,7 @@
 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
 #define PNG_LIBPNG_VER_MAJOR   1
 #define PNG_LIBPNG_VER_MINOR   4
-#define PNG_LIBPNG_VER_RELEASE 4
+#define PNG_LIBPNG_VER_RELEASE 5
 /* This should match the numeric part of the final component of
  * PNG_LIBPNG_VER_STRING, omitting any leading zero:
  */
@@ -392,7 +398,7 @@
  * 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 10404 /* 1.4.4 */
+#define PNG_LIBPNG_VER 10405 /* 1.4.5 */
 
 #ifndef PNG_VERSION_INFO_ONLY
 /* Include the compression library's header */
@@ -1476,7 +1482,7 @@ struct png_struct_def
 /* This triggers a compiler error in png.c, if png.c and png.h
  * do not agree upon the version number.
  */
-typedef png_structp version_1_4_4;
+typedef png_structp version_1_4_5;
 
 typedef png_struct FAR * FAR * png_structpp;
 
@@ -2645,12 +2651,24 @@ PNG_EXPORT(png_bytep,png_get_io_chunk_name)
       ((png_uint_32)(*((buf) + 1)) << 16) + \
       ((png_uint_32)(*((buf) + 2)) << 8) + \
       ((png_uint_32)(*((buf) + 3))))
+
+  /* The following definition introduces an API incompatibility (but not
+   * an ABI incompatibility) with libpng-1.4.0 through 1.4.4.  Prior to
+   * libpng-1.4.5 the macro, which is used by default, returned (incorrectly)
+   * a (png_uint_32), while the function, if used instead, correctly returned
+   * a (png_uint_16).
+   *
+   * Libpng versions 1.0.x and 1.2.x only used a function so are not affected
+   * by this potential API incompatibility between macros.
+   */
 #  define png_get_uint_16(buf) \
-     (((png_uint_32)(*(buf)) << 8) + \
-      ((png_uint_32)(*((buf) + 1))))
+     ((png_uint_16) \
+       (((unsigned int)(*(buf)) << 8) + \
+        ((unsigned int)(*((buf) + 1)))))
+
 #  define png_get_int_32(buf) \
      ((png_int_32)((*(buf) & 0x80) \
-      ? -((png_int_32)((png_get_uint_32(buf) ^ 0xffffffff)+1)) \
+      ? -((png_int_32)((png_get_uint_32(buf) ^ 0xffffffffL) + 1)) \
       : (png_int_32)png_get_uint_32(buf)))
 #else
 PNG_EXPORT(png_uint_32,png_get_uint_32) PNGARG((png_bytep buf));
diff --git a/GRRLIB/lib/png/pngconf.h b/GRRLIB/lib/png/pngconf.h
index 7d17802..7d13828 100644
--- a/GRRLIB/lib/png/pngconf.h
+++ b/GRRLIB/lib/png/pngconf.h
@@ -1,7 +1,7 @@
 
 /* pngconf.h - machine configurable file for libpng
  *
- * libpng version 1.4.4 - September 23, 2010
+ * libpng version 1.4.5 - December 9, 2010
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2010 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/GRRLIB/lib/png/pngget.c b/GRRLIB/lib/png/pngget.c
index 2a43a4d..09ba775 100644
--- a/GRRLIB/lib/png/pngget.c
+++ b/GRRLIB/lib/png/pngget.c
@@ -858,7 +858,7 @@ png_get_unknown_chunks(png_structp png_ptr, png_infop info_ptr,
 
 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
 png_byte PNGAPI
-png_get_rgb_to_gray_status (png_structp png_ptr)
+png_get_rgb_to_gray_status(png_structp png_ptr)
 {
    return (png_byte)(png_ptr? png_ptr->rgb_to_gray_status : 0);
 }
@@ -883,24 +883,24 @@ png_get_compression_buffer_size(png_structp png_ptr)
 /* These functions were added to libpng 1.2.6 and were enabled
  * by default in libpng-1.4.0 */
 png_uint_32 PNGAPI
-png_get_user_width_max (png_structp png_ptr)
+png_get_user_width_max(png_structp png_ptr)
 {
     return (png_ptr? png_ptr->user_width_max : 0);
 }
 png_uint_32 PNGAPI
-png_get_user_height_max (png_structp png_ptr)
+png_get_user_height_max(png_structp png_ptr)
 {
     return (png_ptr? png_ptr->user_height_max : 0);
 }
 /* This function was added to libpng 1.4.0 */
 png_uint_32 PNGAPI
-png_get_chunk_cache_max (png_structp png_ptr)
+png_get_chunk_cache_max(png_structp png_ptr)
 {
     return (png_ptr? png_ptr->user_chunk_cache_max : 0);
 }
 /* This function was added to libpng 1.4.1 */
 png_alloc_size_t PNGAPI
-png_get_chunk_malloc_max (png_structp png_ptr)
+png_get_chunk_malloc_max(png_structp png_ptr)
 {
     return (png_ptr?
        png_ptr->user_chunk_malloc_max : 0);
@@ -910,13 +910,13 @@ png_get_chunk_malloc_max (png_structp png_ptr)
 /* These functions were added to libpng 1.4.0 */
 #ifdef PNG_IO_STATE_SUPPORTED
 png_uint_32 PNGAPI
-png_get_io_state (png_structp png_ptr)
+png_get_io_state(png_structp png_ptr)
 {
     return png_ptr->io_state;
 }
 
 png_bytep PNGAPI
-png_get_io_chunk_name (png_structp png_ptr)
+png_get_io_chunk_name(png_structp png_ptr)
 {
    return png_ptr->chunk_name;
 }
diff --git a/GRRLIB/lib/png/pngpread.c b/GRRLIB/lib/png/pngpread.c
index 61683cc..f8566f2 100644
--- a/GRRLIB/lib/png/pngpread.c
+++ b/GRRLIB/lib/png/pngpread.c
@@ -1109,6 +1109,8 @@ png_push_process_row(png_structp png_ptr)
 
             break;
          }
+
+         default:
          case 6:
          {
             png_push_have_row(png_ptr, png_ptr->row_buf + 1);
@@ -1726,7 +1728,7 @@ png_push_have_row(png_structp png_ptr, png_bytep row)
 }
 
 void PNGAPI
-png_progressive_combine_row (png_structp png_ptr,
+png_progressive_combine_row(png_structp png_ptr,
    png_bytep old_row, png_bytep new_row)
 {
    PNG_CONST int FARDATA png_pass_dsp_mask[7] =
diff --git a/GRRLIB/lib/png/pngpriv.h b/GRRLIB/lib/png/pngpriv.h
index ebf8e53..5ae742f 100644
--- a/GRRLIB/lib/png/pngpriv.h
+++ b/GRRLIB/lib/png/pngpriv.h
@@ -1,7 +1,7 @@
 
 /* pngpriv.h - private declarations for use inside libpng
  *
- * libpng version 1.4.4 - September 23, 2010
+ * libpng version 1.4.5 - December 9, 2010
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2010 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -290,6 +290,9 @@ PNG_EXTERN void png_reset_crc PNGARG((png_structp png_ptr));
 PNG_EXTERN void png_write_data PNGARG((png_structp png_ptr, png_bytep data,
    png_size_t length));
 
+/* Read and check the PNG file signature */
+PNG_EXTERN void png_read_sig PNGARG((png_structp png_ptr, png_infop info_ptr));
+
 /* Read the chunk header (length + type name) */
 PNG_EXTERN png_uint_32 png_read_chunk_header PNGARG((png_structp png_ptr));
 
diff --git a/GRRLIB/lib/png/pngread.c b/GRRLIB/lib/png/pngread.c
index 3ec2df4..bc2edbd 100644
--- a/GRRLIB/lib/png/pngread.c
+++ b/GRRLIB/lib/png/pngread.c
@@ -1,7 +1,7 @@
 
 /* pngread.c - read a PNG file
  *
- * Last changed in libpng 1.4.1 [February 25, 2010]
+ * Last changed in libpng 1.4.5 [December 9, 2010]
  * Copyright (c) 1998-2010 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.)
@@ -214,34 +214,12 @@ void PNGAPI
 png_read_info(png_structp png_ptr, png_infop info_ptr)
 {
    png_debug(1, "in png_read_info");
- 
+
    if (png_ptr == NULL || info_ptr == NULL)
       return;
- 
-   /* If we haven't checked all of the PNG signature bytes, do so now. */
-   if (png_ptr->sig_bytes < 8)
-   {
-      png_size_t num_checked = png_ptr->sig_bytes,
-                 num_to_check = 8 - num_checked;
 
-#ifdef PNG_IO_STATE_SUPPORTED
-      png_ptr->io_state = PNG_IO_READING | PNG_IO_SIGNATURE;
-#endif
-
-      png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
-      png_ptr->sig_bytes = 8;
-
-      if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
-      {
-         if (num_checked < 4 &&
-             png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
-            png_error(png_ptr, "Not a PNG file");
-         else
-            png_error(png_ptr, "PNG file corrupted by ASCII conversion");
-      }
-      if (num_checked < 3)
-         png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
-   }
+   /* Read and check the PNG file signature. */
+   png_read_sig(png_ptr, info_ptr);
 
    for (;;)
    {
@@ -426,7 +404,7 @@ void PNGAPI
 png_read_update_info(png_structp png_ptr, png_infop info_ptr)
 {
    png_debug(1, "in png_read_update_info");
- 
+
    if (png_ptr == NULL)
       return;
    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
@@ -448,7 +426,7 @@ void PNGAPI
 png_start_read_image(png_structp png_ptr)
 {
    png_debug(1, "in png_start_read_image");
- 
+
    if (png_ptr == NULL)
       return;
    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
@@ -465,10 +443,10 @@ png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
       0xff};
    PNG_CONST int png_pass_mask[7] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
    int ret;
- 
+
    if (png_ptr == NULL)
       return;
- 
+
    png_debug2(1, "in png_read_row (row %lu, pass %d)",
       (unsigned long) png_ptr->row_number, png_ptr->pass);
 
@@ -524,6 +502,7 @@ png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
                return;
             }
             break;
+
          case 1:
             if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
             {
@@ -534,6 +513,7 @@ png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
                return;
             }
             break;
+
          case 2:
             if ((png_ptr->row_number & 0x07) != 4)
             {
@@ -544,6 +524,7 @@ png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
                return;
             }
             break;
+
          case 3:
             if ((png_ptr->row_number & 3) || png_ptr->width < 3)
             {
@@ -554,6 +535,7 @@ png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
                return;
             }
             break;
+
          case 4:
             if ((png_ptr->row_number & 3) != 2)
             {
@@ -564,6 +546,7 @@ png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
                return;
             }
             break;
+
          case 5:
             if ((png_ptr->row_number & 1) || png_ptr->width < 2)
             {
@@ -574,6 +557,8 @@ png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
                return;
             }
             break;
+
+         default:
          case 6:
             if (!(png_ptr->row_number & 1))
             {
@@ -724,7 +709,7 @@ png_read_rows(png_structp png_ptr, png_bytepp row,
    png_bytepp dp;
 
    png_debug(1, "in png_read_rows");
- 
+
    if (png_ptr == NULL)
       return;
    rp = row;
@@ -775,7 +760,7 @@ png_read_image(png_structp png_ptr, png_bytepp image)
    png_bytepp rp;
 
    png_debug(1, "in png_read_image");
- 
+
    if (png_ptr == NULL)
       return;
 
@@ -813,7 +798,7 @@ void PNGAPI
 png_read_end(png_structp png_ptr, png_infop info_ptr)
 {
    png_debug(1, "in png_read_end");
- 
+
    if (png_ptr == NULL)
       return;
    png_crc_finish(png_ptr, 0); /* Finish off CRC from last IDAT chunk */
@@ -993,7 +978,7 @@ png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
 #endif
 
    png_debug(1, "in png_destroy_read_struct");
- 
+
    if (png_ptr_ptr != NULL)
       png_ptr = *png_ptr_ptr;
    if (png_ptr == NULL)
@@ -1069,7 +1054,7 @@ png_read_destroy(png_structp png_ptr, png_infop info_ptr,
 #endif
 
    png_debug(1, "in png_read_destroy");
- 
+
    if (info_ptr != NULL)
       png_info_destroy(png_ptr, info_ptr);
 
diff --git a/GRRLIB/lib/png/pngrio.c b/GRRLIB/lib/png/pngrio.c
index 990fe3f..72e6b85 100644
--- a/GRRLIB/lib/png/pngrio.c
+++ b/GRRLIB/lib/png/pngrio.c
@@ -1,7 +1,7 @@
 
 /* pngrio.c - functions for data input
  *
- * Last changed in libpng 1.4.1 [February 25, 2010]
+ * Last changed in libpng 1.4.5 [December 9, 2010]
  * Copyright (c) 1998-2010 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.)
@@ -33,7 +33,7 @@ void /* PRIVATE */
 png_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
 {
    png_debug1(4, "reading %d bytes", (int)length);
- 
+
    if (png_ptr->read_data_fn != NULL)
       (*(png_ptr->read_data_fn))(png_ptr, data, length);
    else
diff --git a/GRRLIB/lib/png/pngrtran.c b/GRRLIB/lib/png/pngrtran.c
index 63ac38b..3252642 100644
--- a/GRRLIB/lib/png/pngrtran.c
+++ b/GRRLIB/lib/png/pngrtran.c
@@ -1,7 +1,7 @@
 
 /* pngrtran.c - transforms the data in a row for PNG readers
  *
- * Last changed in libpng 1.4.2 [May 6, 2010]
+ * Last changed in libpng 1.4.5 [December 9, 2010]
  * Copyright (c) 1998-2010 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.)
@@ -26,7 +26,7 @@ void PNGAPI
 png_set_crc_action(png_structp png_ptr, int crit_action, int ancil_action)
 {
    png_debug(1, "in png_set_crc_action");
- 
+
    if (png_ptr == NULL)
       return;
 
@@ -98,7 +98,7 @@ png_set_background(png_structp png_ptr,
    int need_expand, double background_gamma)
 {
    png_debug(1, "in png_set_background");
- 
+
    if (png_ptr == NULL)
       return;
    if (background_gamma_code == PNG_BACKGROUND_GAMMA_UNKNOWN)
@@ -686,6 +686,11 @@ png_set_rgb_to_gray_fixed(png_structp png_ptr, int error_action,
               break;
 
       case 3: png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR;
+         break;
+
+      default:
+         png_error(png_ptr, "invalid error action in png_set_rgb_to_gray");
+         break;
    }
    if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
 #ifdef PNG_READ_EXPAND_SUPPORTED
@@ -828,6 +833,8 @@ png_init_read_transformations(png_structp png_ptr)
                }
                break;
 
+            default:
+
             case 8:
 
             case 16:
@@ -1028,6 +1035,9 @@ png_init_read_transformations(png_structp png_ptr)
                   gs = 1.0 / (png_ptr->background_gamma *
                      png_ptr->screen_gamma);
                   break;
+
+               default:
+                  png_error(png_ptr, "invalid background gamma type");
             }
 
             png_ptr->background_1.gray = (png_uint_16)(pow(
@@ -1626,6 +1636,9 @@ png_do_unpack(png_row_infop row_info, png_bytep row)
             }
             break;
          }
+
+         default:
+            break;
       }
       row_info->bit_depth = 8;
       row_info->pixel_depth = (png_byte)(8 * row_info->channels);
@@ -1682,6 +1695,9 @@ png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits)
 
       switch (row_info->bit_depth)
       {
+         default:
+            break; 
+
          case 2:
          {
             png_bytep bp;
@@ -2798,6 +2814,9 @@ png_do_background(png_row_infop row_info, png_bytep row,
                   }
                   break;
                }
+
+               default:
+                  break;
             }
             break;
          }
@@ -3230,6 +3249,9 @@ png_do_background(png_row_infop row_info, png_bytep row,
             }
             break;
          }
+
+         default:
+            break;
       }
 
       if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
@@ -3428,6 +3450,9 @@ png_do_gamma(png_row_infop row_info, png_bytep row,
             }
             break;
          }
+
+         default:
+            break;
       }
    }
 }
@@ -3522,6 +3547,9 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row,
                }
                break;
             }
+
+            default:
+               break;
          }
          row_info->bit_depth = 8;
          row_info->pixel_depth = 8;
@@ -3672,6 +3700,9 @@ png_do_expand(png_row_infop row_info, png_bytep row,
                   }
                   break;
                }
+
+               default:
+                  break;
             }
 
             row_info->bit_depth = 8;
diff --git a/GRRLIB/lib/png/pngrutil.c b/GRRLIB/lib/png/pngrutil.c
index 6a7437e..9bbebc0 100644
--- a/GRRLIB/lib/png/pngrutil.c
+++ b/GRRLIB/lib/png/pngrutil.c
@@ -1,7 +1,7 @@
 
 /* pngrutil.c - utilities to read a PNG file
  *
- * Last changed in libpng 1.4.4 [August 26, 2010]
+ * Last changed in libpng 1.4.5 [December 9, 2010]
  * Copyright (c) 1998-2010 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.)
@@ -23,23 +23,29 @@
 png_uint_32 PNGAPI
 png_get_uint_31(png_structp png_ptr, png_bytep buf)
 {
-   png_uint_32 i = png_get_uint_32(buf);
-   if (i > PNG_UINT_31_MAX)
+   png_uint_32 val = png_get_uint_32(buf);
+
+   if (val > PNG_UINT_31_MAX)
      png_error(png_ptr, "PNG unsigned integer out of range");
-   return (i);
+   return (val);
 }
+
 #ifndef PNG_USE_READ_MACROS
+/* The parentheses around "PNGAPI function_name" in the following three
+ * functions are necessary because they allow the macros to co-exist with
+ * these (unused but exported) functions.
+ */
+
 /* Grab an unsigned 32-bit integer from a buffer in big-endian format. */
 png_uint_32 (PNGAPI
 png_get_uint_32)(png_bytep buf)
 {
-   png_uint_32 i =
-       ((png_uint_32)(*(buf    )) << 24) +
-       ((png_uint_32)(*(buf + 1)) << 16) +
-       ((png_uint_32)(*(buf + 2)) <<  8) +
-       ((png_uint_32)(*(buf + 3))      ) ;
+   png_uint_32 uval = png_get_uint_32(buf);
+   if ((uval & 0x80000000L) == 0) /* non-negative */
+      return uval;
 
-   return (i);
+   uval = (uval ^ 0xffffffffL) + 1;  /* 2's complement: -x = ~x+1 */
+   return -(png_int_32)uval;
 }
 
 /* Grab a signed 32-bit integer from a buffer in big-endian format.  The
@@ -50,26 +56,65 @@ png_get_uint_32)(png_bytep buf)
 png_int_32 (PNGAPI
 png_get_int_32)(png_bytep buf)
 {
-   png_uint_32 u = png_get_uint_32(buf);
-   if ((u & 0x80000000) == 0) /* non-negative */
-      return u;
+   png_uint_32 uval = png_get_uint_32(buf);
+   if ((uval & 0x80000000L) == 0) /* non-negative */
+      return uval;
 
-   u = (u ^ 0xffffffff) + 1;  /* 2's complement: -x = ~x+1 */
-   return -(png_int_32)u;
+   uval = (uval ^ 0xffffffffL) + 1;  /* 2's complement: -x = ~x+1 */
+   return -(png_int_32)uval;
 }
 
 /* Grab an unsigned 16-bit integer from a buffer in big-endian format. */
 png_uint_16 (PNGAPI
 png_get_uint_16)(png_bytep buf)
 {
-   png_uint_16 i =
-       ((png_uint_32)(*buf) << 8) +
-       ((png_uint_32)(*(buf + 1)));
+   /* ANSI-C requires an int value to accomodate at least 16 bits so this
+    * works and allows the compiler not to worry about possible narrowing
+    * on 32 bit systems.  (Pre-ANSI systems did not make integers smaller
+    * than 16 bits either.)
+    */
+   unsigned int val =
+       ((unsigned int)(*buf) << 8) +
+       ((unsigned int)(*(buf + 1)));
 
-   return (i);
+   return (png_uint_16)val;
 }
 #endif /* PNG_USE_READ_MACROS */
 
+/* Read and check the PNG file signature */
+void /* PRIVATE */
+png_read_sig(png_structp png_ptr, png_infop info_ptr)
+{
+   png_size_t num_checked, num_to_check;
+
+   /* Exit if the user application does not expect a signature. */
+   if (png_ptr->sig_bytes >= 8)
+      return;
+
+   num_checked = png_ptr->sig_bytes;
+   num_to_check = 8 - num_checked;
+
+#ifdef PNG_IO_STATE_SUPPORTED
+   png_ptr->io_state = PNG_IO_READING | PNG_IO_SIGNATURE;
+#endif
+
+   /* The signature must be serialized in a single I/O call. */
+   png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
+   png_ptr->sig_bytes = 8;
+
+   if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
+   {
+      if (num_checked < 4 &&
+          png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
+         png_error(png_ptr, "Not a PNG file");
+
+      else
+         png_error(png_ptr, "PNG file corrupted by ASCII conversion");
+   }
+   if (num_checked < 3)
+      png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
+}
+
 /* Read the chunk header (length + type name).
  * Put the type name into png_ptr->chunk_name, and return the length.
  */
@@ -80,32 +125,31 @@ png_read_chunk_header(png_structp png_ptr)
    png_uint_32 length;
 
 #ifdef PNG_IO_STATE_SUPPORTED
-   /* Inform the I/O callback that the chunk header is being read.
-    * PNG_IO_CHUNK_HDR requires a single I/O call.
-    */
    png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_HDR;
 #endif
 
-   /* Read the length and the chunk name */
+   /* Read the length and the chunk name.
+    * This must be performed in a single I/O call.
+    */
    png_read_data(png_ptr, buf, 8);
    length = png_get_uint_31(png_ptr, buf);
 
-   /* Put the chunk name into png_ptr->chunk_name */
+   /* Put the chunk name into png_ptr->chunk_name. */
    png_memcpy(png_ptr->chunk_name, buf + 4, 4);
 
    png_debug2(0, "Reading %s chunk, length = %lu",
       png_ptr->chunk_name, length);
 
-   /* Reset the crc and run it over the chunk name */
+   /* Reset the crc and run it over the chunk name. */
    png_reset_crc(png_ptr);
    png_calculate_crc(png_ptr, png_ptr->chunk_name, 4);
 
-   /* Check to see if chunk name is valid */
+   /* Check to see if chunk name is valid. */
    png_check_chunk_name(png_ptr, png_ptr->chunk_name);
 
 #ifdef PNG_IO_STATE_SUPPORTED
-   /* Inform the I/O callback that chunk data will (possibly) be read.
-    * PNG_IO_CHUNK_DATA does NOT require a specific number of I/O calls.
+   /* It is unspecified how many I/O calls will be performed
+    * during the serialization of the chunk data.
     */
    png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_DATA;
 #endif
@@ -119,6 +163,7 @@ png_crc_read(png_structp png_ptr, png_bytep buf, png_size_t length)
 {
    if (png_ptr == NULL)
       return;
+
    png_read_data(png_ptr, buf, length);
    png_calculate_crc(png_ptr, buf, length);
 }
@@ -138,6 +183,7 @@ png_crc_finish(png_structp png_ptr, png_uint_32 skip)
    {
       png_crc_read(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
    }
+
    if (i)
    {
       png_crc_read(png_ptr, png_ptr->zbuf, i);
@@ -152,11 +198,13 @@ png_crc_finish(png_structp png_ptr, png_uint_32 skip)
       {
          png_chunk_warning(png_ptr, "CRC error");
       }
+
       else
       {
          png_chunk_benign_error(png_ptr, "CRC error");
          return (0);
       }
+
       return (1);
    }
 
@@ -179,6 +227,7 @@ png_crc_error(png_structp png_ptr)
           (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
          need_crc = 0;
    }
+
    else                                                    /* critical */
    {
       if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
@@ -186,11 +235,10 @@ png_crc_error(png_structp png_ptr)
    }
 
 #ifdef PNG_IO_STATE_SUPPORTED
-   /* Inform the I/O callback that the chunk CRC is being read */
-   /* PNG_IO_CHUNK_CRC requires the I/O to be done at once */
    png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_CRC;
 #endif
 
+   /* The chunk CRC must be serialized in a single I/O call. */
    png_read_data(png_ptr, crc_bytes, 4);
 
    if (need_crc)
@@ -198,6 +246,7 @@ png_crc_error(png_structp png_ptr)
       crc = png_get_uint_32(crc_bytes);
       return ((int)(crc != png_ptr->crc));
    }
+
    else
       return (0);
 }
@@ -237,6 +286,7 @@ png_inflate(png_structp png_ptr, const png_byte *data, png_size_t size,
             if (avail < copy) copy = avail;
             png_memcpy(output + count, png_ptr->zbuf, copy);
          }
+
          count += avail;
       }
 
@@ -270,9 +320,11 @@ png_inflate(png_structp png_ptr, const png_byte *data, png_size_t size,
                case Z_BUF_ERROR:
                   msg = "Buffer error in compressed datastream in %s chunk";
                   break;
+
                case Z_DATA_ERROR:
                   msg = "Data error in compressed datastream in %s chunk";
                   break;
+
                default:
                   msg = "Incomplete compressed datastream in %s chunk";
                   break;
@@ -372,6 +424,7 @@ png_decompress_chunk(png_structp png_ptr, int comp_type,
             png_warning(png_ptr, "png_inflate logic error");
             png_free(png_ptr, text);
          }
+
          else
           png_warning(png_ptr, "Not enough memory to decompress chunk");
       }
@@ -3109,17 +3162,10 @@ png_read_finish_row(png_structp png_ptr)
          {
             while (!png_ptr->idat_size)
             {
-               png_byte chunk_length[4];
-
                png_crc_finish(png_ptr, 0);
-
-               png_read_data(png_ptr, chunk_length, 4);
-               png_ptr->idat_size = png_get_uint_31(png_ptr, chunk_length);
-               png_reset_crc(png_ptr);
-               png_crc_read(png_ptr, png_ptr->chunk_name, 4);
+               png_ptr->idat_size = png_read_chunk_header(png_ptr);
                if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
                   png_error(png_ptr, "Not enough image data");
-
             }
             png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size;
             png_ptr->zstream.next_in = png_ptr->zbuf;
diff --git a/GRRLIB/lib/png/pngset.c b/GRRLIB/lib/png/pngset.c
index 90ef1b4..92d2408 100644
--- a/GRRLIB/lib/png/pngset.c
+++ b/GRRLIB/lib/png/pngset.c
@@ -1,7 +1,7 @@
 
 /* pngset.c - storage of image information into info struct
  *
- * Last changed in libpng 1.4.1 [February 25, 2010]
+ * Last changed in libpng 1.4.5 [December 9, 2010]
  * Copyright (c) 1998-2010 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.)
@@ -690,6 +690,13 @@ png_set_text_2(png_structp png_ptr, png_infop info_ptr, png_textp text_ptr,
       if (text_ptr[i].key == NULL)
           continue;
 
+      if (text_ptr[i].compression < PNG_TEXT_COMPRESSION_NONE ||
+          text_ptr[i].compression >= PNG_TEXT_COMPRESSION_LAST)
+      {
+         png_warning(png_ptr, "text compression mode is out of range");
+         continue;
+      }
+
       key_len = png_strlen(text_ptr[i].key);
 
       if (text_ptr[i].compression <= 0)
@@ -1004,7 +1011,7 @@ png_set_unknown_chunk_location(png_structp png_ptr, png_infop info_ptr,
 
 #ifdef PNG_MNG_FEATURES_SUPPORTED
 png_uint_32 PNGAPI
-png_permit_mng_features (png_structp png_ptr, png_uint_32 mng_features)
+png_permit_mng_features(png_structp png_ptr, png_uint_32 mng_features)
 {
    png_debug(1, "in png_permit_mng_features");
 
@@ -1118,7 +1125,7 @@ png_set_invalid(png_structp png_ptr, png_infop info_ptr, int mask)
 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
 /* This function was added to libpng 1.2.6 */
 void PNGAPI
-png_set_user_limits (png_structp png_ptr, png_uint_32 user_width_max,
+png_set_user_limits(png_structp png_ptr, png_uint_32 user_width_max,
     png_uint_32 user_height_max)
 {
    /* Images with dimensions larger than these limits will be
@@ -1133,7 +1140,7 @@ png_set_user_limits (png_structp png_ptr, png_uint_32 user_width_max,
 
 /* This function was added to libpng 1.4.0 */
 void PNGAPI
-png_set_chunk_cache_max (png_structp png_ptr,
+png_set_chunk_cache_max(png_structp png_ptr,
    png_uint_32 user_chunk_cache_max)
 {
     if (png_ptr)
@@ -1142,7 +1149,7 @@ png_set_chunk_cache_max (png_structp png_ptr,
 
 /* This function was added to libpng 1.4.1 */
 void PNGAPI
-png_set_chunk_malloc_max (png_structp png_ptr,
+png_set_chunk_malloc_max(png_structp png_ptr,
    png_alloc_size_t user_chunk_malloc_max)
 {
     if (png_ptr)
diff --git a/GRRLIB/lib/png/pngwtran.c b/GRRLIB/lib/png/pngwtran.c
index 9cf095b..0248b66 100644
--- a/GRRLIB/lib/png/pngwtran.c
+++ b/GRRLIB/lib/png/pngwtran.c
@@ -195,6 +195,9 @@ png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
                *dp = (png_byte)v;
             break;
          }
+
+         default:
+            break;
       }
       row_info->bit_depth = (png_byte)bit_depth;
       row_info->pixel_depth = (png_byte)(bit_depth * row_info->channels);
diff --git a/GRRLIB/lib/png/pngwutil.c b/GRRLIB/lib/png/pngwutil.c
index dc4aa14..b44ab9f 100644
--- a/GRRLIB/lib/png/pngwutil.c
+++ b/GRRLIB/lib/png/pngwutil.c
@@ -246,10 +246,12 @@ png_text_compress(png_structp png_ptr,
     */
 
    /* Set up the compression buffers */
+   /* TODO: the following cast hides a potential overflow problem. */
    png_ptr->zstream.avail_in = (uInt)text_len;
+   /* NOTE: assume zlib doesn't overwrite the input */
    png_ptr->zstream.next_in = (Bytef *)text;
-   png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
-   png_ptr->zstream.next_out = (Bytef *)png_ptr->zbuf;
+   png_ptr->zstream.avail_out = png_ptr->zbuf_size;
+   png_ptr->zstream.next_out = png_ptr->zbuf;
 
    /* This is the same compression loop as in png_write_row() */
    do