this has also happened to me (where I have used and avatar and then had someone notify me that I was using their picture) when I first came here. i dont know if this is how it still works but when I first came here someone notified me that I was using their personal picture/avatar. I discovered that they had left the site with out deleting their photos and avatars first and that their photos and avatars were somehow automatically added to the selection list for avatars that anyone can use.

if it still works this way (avatars and photos automatically added to the community selection list when someone leaves them here on the site when they leave) my suggestion is that if anyone plans on deleting their accounts to go through and delete their pictures and avatar off their account before asking for the deletion. this way their personal photos\personal avatars wont end up in the community selection list.