What's not allowed is to hotlink the avatar straight to Suikosource (or any other sites that isn't yours). Having character art has nothing to do with hotlinking.
So basically if you want to use avatar, make sure to hotlink it to your own site or image hosting sites such as imageshack or photobucket or others if you know any.
The new chief of moderating team. If you notice any problems within the discussion forum, do inform me. Thank you.