Hmmm... I've gone through all your settings and you should be able to. Are you looking in the right place? Go to the top of this page, "Forum Actions" (Under the "What's new" tab), click "Edit Profile". In the new page look on the left for a box titled "My Settings". WIthin there is the option to "Edit Avatar". You can then upload it and save changes.
I know, it's a bit more awkward than before, but you should see what I'm dealing with on the back end!
Not much I can do about that - they have to log in and clear their inbox! They'll be getting email notifications that their inbox is full and someone is trying to send them messages, though. Let me know who it is and I'll send a nudge email.