Has anyone tested if this works?
It shouldn't work. If it does, it's a bug and should be fixed.
I still see animated avatars for campaigns.
Those are old avatars:
OK, APNGs are now detected. Old ones are grandfathered for now, in part because people have ongoing campaigns, but in the future I might (or might not) go through and remove them.
I was editing some pictures in PS a few days ago when I realized it have a feature for making gifs. I tried making a rather crude animated version of my avatar, only to find I can't upload it.
You have the campaigns that overdid it to thank for that.