(write this down!)
1. go to USER CP up top there
2. go to EDIT PROFILE
3. Scroll down to the SIGNATURE bit
4. type (or copy/paste) [.img]http://members.truepath.com/arkansasmommies/liltiger.gif[/.img]
5. scroll down and choose save (not reset)

TAKE THE . out of the IMG tags, I had to put them there to avoid showing the picture so you could see the URL that you need to copy/paste!