Created attachment 8535538 [details] GIF with no frame delay To reproduce: Display attached image with Firefox 34.0.5. Since the browser defaults to rescale-to-window, click once to set image scaling to 1:1. Observe the colour of the pixel at coordinates 1313,892 relative to the top-left corner of the image. Actual result: Colour is white. Expected result: Colour should be a deep blue. Further information: This bug does not occur with Opera 12.16, Chromium 39.0.2171.65, gifview (from gifsicle 1.87). When the GIF frame delay is changed from none to 1 centisecond each, Firefox renders the pixel correctly.
Created attachment 8535539 [details] GIF with 1 centisecond frame delay each File contains the same encoded image data as above, just the frame delay is different.
It seems to be same between Firefox34 and IE11 on windows7x64.
I'm seeing the reported behavior using a recent build from hg tip (Firefox37.0a1 changeset 219326), on Ubuntu.
A recent regression?
Fixed in bug 1126330. We now play back the 0-frame-delay GIF just like Blink.
Still broken in Firefox 44. Please retest.
(In reply to Lars Dɪᴇᴄᴋᴏᴡ from comment #6) > Still broken in Firefox 44. Please retest. This looks fine on my end. Can you please provide more details?
Created attachment 8717731 [details] bug1110686.png I don't know, what more details do you need? Screenshot of the rendering defect highlighted with a pink circle attached.
(In reply to Lars Dɪᴇᴄᴋᴏᴡ from comment #8) > Created attachment 8717731 [details] > bug1110686.png > Screenshot of the rendering defect highlighted with a pink circle attached. Thanks, I can see the issue now on the GIF with no frame delay. I'm updating the summary to more accurately describe the issue. I'll see if I can track down if this was ever fixed and if so, what fixed it and what regressed it.
Okay, so I've tested and reproduced the issue Firefox 44.0, 43.0, 42.0 and 41.0. I think it's safe to say that this issue was never fixed. Seth, do you have any ideas as to what could be happening here?