I'm trying to help a new meme along:

http://www.corante.com/copyfight/

http://www.google.com/search?ie=UTF-8&oe=UTF-8&q=copyfight&domains=boingboing.net&sitesearch=boingboing.net

The fight being that your avatar is fair use of an image, and doesn't infringe.  Unfortunately I'd like to say this is a given, but it's not.