Gravatar: Setting one from within wordpress

Is it possible to set a gravatar within wordpress? Even if the feature doesn’t exist, is it something that can be done or does gravatar force people to go to their website?

I run a bbpress community and I want to let users upload their own avatars but I found that every single avatar plugin does not overwrite previous avatar uploads so it just consumes tons of space and makes a mess.

With gravatars my main issue is telling people to leave the site to use a not so pretty and heavily branded one and then to come back. If there were a way to let users choose a gravatar within my website that would be good. Is it possible?