pageoneresults - 3:57 pm on May 25, 2010 (gmt 0)
what if they were optional? If yours is turned on, then you see everyone elses?
Optional would be a good way to approach it. You'll definitely need lots of checks and balances in place during the upload routines. Folks will quickly upload a 500k avatar and not think twice about it. Keep them small both dimension and byte size and I think it would be doable. Avatars off by default though.
I'd definitely consider bandwidth challenges in this instance. If you keep the initial avatar specifications lean and mean, it would still have an impact but not nearly as bad as it could be.