I don’t know if you noticed but I literally quoted a post where theymos states that he made the system detect and disallow APNGs images. My point is that this was possible just because there was no system to detrct it, but it was not intended to be allowed.

At first I did not realize how annoying it could be to a majority of people with these animated avatars. I liked them and thought they were great for marketing purposes but I'll no longer use them and I am in the process of having everyone in my campaigns change theirs for a static avatar instead. Sorry!