http://bugs.winehq.org/show_bug.cgi?id=58757
--- Comment #7 from Ian superian@gmail.com --- Thanks for the hand-holding.
As well as the lines showing things like reading EXIF data are not implemented, there's one that sounds a likely candidate for this:
0128:fixme:wincodecs:copypixels_to_64bppRGBA Unimplemented conversion path 18.