So, this suggestion is to allow GIF's as profile pictures that are larger than 50x50? But, also be below 50kb. You will struggle to find a GIF that is below 50kb as well as 200x200 in size. Even the basic gif I placed above is more than 100kb in size. I think having Gif's as profile pictures is a good thing, we'd just be incredibly limited on what images we can actually use. I've only found very basic, very boring gifs that we would be able to use. Possibly change the size to 150kb, or something?
Sure, it's possible. Though, the only way to properly give a large decrease in a gif's size is to remove different frames of the images within it.
If it's possible, 150kb will allow us to have pretty good GIF's as our profile pictures. Though, most one's that are used in people signatures are around 500-800, probably even into the Mb's.