GIF won't open on OS X/Safari after optimisation about gifsicle

[kohler]

Thanks for providing this. I have boiled it down the following one-frame, 3-color GIF, which Safari refuses to display:

Contrast that GIF with this one-frame, 3-color GIF, with the same data but encoded very slightly differently, which Safari does display:

[kohler]

I am mystified by this problem. It seems unlikely to be a gifsicle bug (and likely to be a Safari/Webkit bug). I tried to extract the Webkit nightly GIF LZW decoder from Safari for debugging purposes, and it appears to handle the problematic image content OK, so the problem may be elsewhere. It may, or may not, be relevant that the “broken” GIF content diverges from the “fixed” GIF content at offset 0x1101 into the file.

[kohler]

I reported the bug as a Safari/Webkit bug to the webkit.org bug tracker:

https://bugs.webkit.org/show_bug.cgi?id=149610

And the bug has been fixed in OS X 10.11. Thanks for the report!

[jak]

Hey, thank you for your help in finding and reporting the issue!