Check out the album, download the image you’d like to use, and you’ll be able to re-upload it here on the forums as your personal avatar icon!
Want to create avatars that everyone can use? Just create a square image file – we recommended 300 x 300 pixels – and post it to this discussion as a reply.
And, why not, here’s a background cobbled together from all the pictures where it isn’t covered, then smudged together for anyone to make their own smudgy portraits over top of: