Firefox Support Forum

I can't even open the downloaded .gif files on my computer. Not able to upload them to image sharing web sites: because they state the file is corrupted. This has been happening since the middle of the summer 2015 when firefox did an software update. .gif files can only be viewed by internet explorer because that is the coding of the file. Before that summer update, there was no problem and then the next day, I could not view .gif files downloaded with the new version. I even left firefox. Had to completely uninstall it and download another browser, which I don't like to continue my work with .gif files. I have redownloaded firefox and I want to use my favorite browser.

How do I fix this issue with .gif files? My OS is Windows 8.1 and don't tell me to upgrade to OS 10. Will not do it. I've heard too many problems with image software not working properly: even windows error of OS Not Found. So, not going there, don't suggest it.

1) Start playing an animated gif Close Firefox See Firefox task still running in windows 10 Task Manager kill the task 2) Open Firefox Click on multiple animated gifs (15, for example) Close Firefox See 15 Firefox tasks still running in windows 10 Task Manager

Examples of broken gifs:

https://twitter.com/wannaODIN_/status/1169143681976283136

https://twitter.com/RedTestament/status/1169139822100930561

https://twitter.com/_t3nshi/status/1169122796573736960

As far as I can tell, this is mainly a Windows 7 problem. I have done a fair bit of testing with gifs I've made myself, and while I don't exactly know how gif "encoding" or whatever works, it seems to be a problem with how Twitter converts certain gif versions.

If I make a gif with Aseprite 1.2.13-x64 the gifs do not work, and show up as black. However you can still download them as a video, reupload them, and then they work, which is kinda weird but I assume twitter re-converts the videos into something else.

However if I make the same gif with Aseprite 1.2.9 which is at least a year older, they work on Twitter.

I've seen some references about H.264 Level 5.2 not working on Windows 7, and maybe that might be the issue? If so, is there any way to get Level 5.2 media to play on Windows 7? https://bugzilla.mozilla.org/show_bug.cgi?id=1479203#c10

Using MediaInfo to check the files of the videos in question they say that they are using AVC (Main@L5.2) (CABAC / 4 Ref Frames), while the "gifs" (yes I know that they are just videos on Twitter) that DO work are AVC (Main@L5).

I am using Firefox 46.0.1. I did not encounter this bug before this update.

I have sensory processing issues. Flashing, zooming, parallax, etc. animation can trigger migraines, and flashing safety signals have triggered seizures, possibly due to the Bucha effect/flicker vertigo. I don't have epilepsy.

I currently use QuickJava to block Gifs and Flash and sometimes block Javascript.

Unfortunately, if I try to "view image info," it no longer blocks Gifs. So instead of seeing the image info, I see pain.

I don't know where the change is.

FF 43.0.3 on Win7 x64 A long page downloads an animated GIF off screen. The page will scroll normally until the GIF needs to be shown. At that point the cursor goes into "wait", and the CPU maxes for that thread for 10-20 seconds per GIF. During this time Windows has marked the program as "not responsive". Eventually the GIF is shown and FF becomes responsive again.