gdarwin,
zokissima showed it a bit above.
i'll paste it again here:
Go into your profile, and under Signature, type "[ img]" then URL of pic then "[ /img]"
So, let's say there's a pic that you want to use, and the address (for exaple) is
"http://www.finescale.com/pics/bs.jpg"
In your signature, just type in:
"[ img]http://www.finescale.com/pics/bs.jpg[ /img]"
I had to do this with quotes and spaces between the [ and img and [ and /. Just do this without the quotations and spaces
just put the text he shows in your sig, but w/o the spaces & quotes.
the problem is, we can't show EXACTLY what to type on the forum, as it would simply interpret it as an instruction and embed the image.