diff -ru4NwbB libpng-1.4.5/png.h libpng-1.4.6beta01/png.h
--- libpng-1.4.5/png.h	2010-12-09 07:48:11.265430061 -0600
+++ libpng-1.4.6beta01/png.h	2010-12-28 21:43:27.000416124 -0600
@@ -152,8 +152,9 @@
  *    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]
+ *    1.4.6beta01             14    10406  14.so.14.6[.0]
  *
  *    Henceforth the source version will match the shared-library major
  *    and minor numbers; the shared-library major version number will be
  *    used for changes in backward compatibility, as it is intended.  The
diff -ru4NwbB libpng-1.4.5/pngrtran.c libpng-1.4.6beta01/pngrtran.c
--- libpng-1.4.5/pngrtran.c	2010-12-09 07:48:11.359864654 -0600
+++ libpng-1.4.6beta01/pngrtran.c	2010-12-28 21:43:27.093209346 -0600
@@ -1007,9 +1007,9 @@
              * to a simple alpha channel strip.
              */
             png_ptr->transformations &= ~PNG_BACKGROUND;
             png_ptr->transformations &= ~PNG_GAMMA;
-            png_ptr->transformations |= PNG_STRIP_ALPHA;
+            png_ptr->flags |= PNG_FLAG_STRIP_ALPHA;
          }
          /* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */
          else
          /* color_type != PNG_COLOR_TYPE_PALETTE */
@@ -1130,9 +1130,9 @@
       }
 
       /* Handled alpha, still need to strip the channel. */
       png_ptr->transformations &= ~PNG_BACKGROUND;
-      png_ptr->transformations |= PNG_STRIP_ALPHA;
+      png_ptr->flags |= PNG_FLAG_STRIP_ALPHA;
    }
 #endif /* PNG_READ_BACKGROUND_SUPPORTED */
 
 #ifdef PNG_READ_SHIFT_SUPPORTED