PNG_TRANSFORM_STRIP_FILLER_AFTER 1604 pngwrite.c           (PNG_TRANSFORM_STRIP_FILLER_AFTER|PNG_TRANSFORM_STRIP_FILLER_BEFORE))
PNG_TRANSFORM_STRIP_FILLER_AFTER 1607 pngwrite.c           if (transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER)