No problemo.
Probably first item to enable would be:
Control Panel » Display Options [-] Topic Display Options
Enable Show User Avatars?

Second would be:
Control Panel » Site Permissions
Can specify a remote avatar
Can choose a stock avatars
Enter a 1 for each group allowed

Also the user may need to enable the avatar display in mystuff?edit preferences
to see others avatars.

Blue Man Group
There is no such thing as stupid questions. Just stupid answers