github.com - see bug description

[webcompat-bot]

URL: python-pillow/Pillow#8003 (comment)

Browser / Version: Firefox 125.0
Operating System: Mac OS X 10.15
Tested Another Browser: Yes Chrome

Problem type: Something else
Description: GIF rendering incorrectly
Steps to Reproduce:
Over at the Python library Pillow, there was a report of a GIF that rendered incorrectly when viewed in Firefox.

However, after some investigation, it would seem that it is only rendering incorrectly when Graphic Control Extension blocks are not present, even if the missing blocks contain no information, and despite the fact that the GIF specification describes them as being optional.

I understand that perhaps this was a deliberate deviation from the spec according to some established convention of use, or perhaps something was missed in the analysis so far.

Browser Configuration

• None

From webcompat.com with ❤️

[azlata]

We appreciate your report but based on your description this is not a compatibility issue.

I tried to open that GIF using both Firefox and Chrome, and no difference was observed.

Tested on:
• Browser / Version: Firefox Release 125.0.3 / Chrome 124.0.6367.92
• Operating System: Mac OS

For this project we try to focus our efforts on layouts and content that works as expected on a browser but not on the other. Closing this as non-compat.

[qa_18/2024]

[Yay295]

This is what I see with Firefox 125.0.2 on Windows 10, after the gif has first filled up with random pixels and then started clearing them back to black. The random pixel area is correct for both, but the re-cleared black area is not black with the second one.

[azlata]

Thanks for the report, I was able to reproduce the issue using Firefox Release and Firefox Nightly. but not on Chrome. Reproducible issues are moved to our Bugzilla component, please see: https://bugzilla.mozilla.org/show_bug.cgi?id=1895712

Closing this as moved.

[inv_19/2024]