[_ck_]

A fixed list of avatars would be easy to do, you just upload them yourself into a folder you decide and then have php do a glob of the files in that directory and present them to the member as a form with a radio select. Whatever they chose gets written by name to the user metadata.

Then you just need simple code in the display post template to show their chosen avatar.

It would be much safer and faster than other avatar methods.