There is a script running in the background that detects faces and is cropping just the face. So very soon it will be only faces and all the same size (well as much as a robot can do anyways, then us humans will need to fix the rest).
And as you know that if you are logged in you can disable them permanently. Just check "remember me" and that way whenever you browse to BZ it will keep you logged in.
Is there a reason you dont want to stay logged in? Unfortunately its a difficult problem to track guests and give them options similar to members.