The -strip option was excluding the PNG tRNS chunk.

diff --git a/MagickCore/image.c b/MagickCore/image.c
index 1f8610c2fcdfdc332ca6aedf04aa8ad284bf7ad5..9f183592d28d1d0955782dac97c25daafee55237 100644 (file)
--- a/MagickCore/image.c
+++ b/MagickCore/image.c
@@ -4059,7 +4059,7 @@ MagickExport MagickBooleanType StripImage(Image *image)
   (void) DeleteImageProperty(image,"comment");
   (void) DeleteImageProperty(image,"date:create");
   (void) DeleteImageProperty(image,"date:modify");
-  (void) SetImageArtifact(image,"png:include-chunk","none,gama");
+  (void) SetImageArtifact(image,"png:include-chunk","none,trns,gama");
   return(MagickTrue);
 }
 \f

diff --git a/coders/png.c b/coders/png.c
index d54ff54e286ad3103d1c5d92b6c8411ac1aecbe0..8b559d824db1c7ede3904f396e36847d37b614aa 100644 (file)
--- a/coders/png.c
+++ b/coders/png.c
@@ -11005,7 +11005,7 @@ static MagickBooleanType WritePNGImage(const ImageInfo *image_info,
    * is forced to be 4 or 6 (GRAY_ALPHA or RGB_ALPHA).
    *
    * The -strip option causes StripImage() to set the png:include-chunk
-   * artifact to "none,gama".
+   * artifact to "none,trns,gama".
    */
 
   mng_info->ping_exclude_bKGD=MagickFalse;