http://bugs.winehq.org/show_bug.cgi?id=17617
--- Comment #28 from Vincent Povirk madewokherd@gmail.com 2009-11-29 18:56:20 --- The program is loading a GIF file that is missing a Trailer (or TERMINATE_RECORD_TYPE, as ungif calls it). I can make the image load by appending a ; to the end of the file or hacking the code to accept this.
The Trailer seems to be required by http://www.w3.org/Graphics/GIF/spec-gif89a.txt, but it seems other programs can display the broken file just fine.