http://bugs.winehq.org/show_bug.cgi?id=34942
--- Comment #3 from Vincent Povirk madewokherd@gmail.com 2013-11-20 10:42:20 CST --- Odd, I guess the width of the rectangle passed to WriteSource doesn't match the size of the PngFrameEncode. Can you check the size of prc in PngFrameEncode_WriteSource?
It could also be interesting to know the size of the bitmap source.