I was just trying to see what kind of hat Shane is wearing in his profile pic.
This is the image link : http://a.wordpress.com/avatar/shaneosullivan-32.jpg
Just out of curiosity, i modified the url and changed it to : http://a.wordpress.com/avatar/shaneosullivan-128.jpg
and it works. You get to see a 128X128 picture. I tried for 256, dint work :(
Summary : Wordpress stores different image sizes for each(as blogger has), or shane has them :)