I'm glad you like it, Andy, and I wish I could take credit for it, but it belongs to TS. If you go to the "Profile" section, you get a choice of "avatars" to upload along side your Displayed Name. There are pages & pages of them! I just chose one that seemed to tell the world how artificial I really am.
The administrators of TS can give you permission or not -- but it is very easy to download an image and then save it, and use it just like you would use any clip art. Click-&-hold with your Mac mouse, or right-click with your PC mouse, and you will get the option to download the image.
Good luck!