So you want a 3.5M avatar?

Honestly we keep the sizes down to maintain site usability and speed. If everyone was given a 3M avatar limit, that's a lot of data for folks to download and some folks would never have them load, regardless of where they are hosted. It's not about the storage on our end, but more about the user experience.

You should be able to get a pretty solid animated gif avatar in that size with a little effort.