Inside of your signature you use UBB code. You first must have your picture uploaded to the internet, and have the URL for it.
Then you place the image inside of [img] and [/img]
If you want a place to host images quickly and easily I recomend you try
www.tripod.lycos.co.uk if you don't already have webspace which offers remote hosting.
If you don't feel like making your own account, E-mail your signature pic to me and I'll then E-mail the code to put in your signature back to you.
I'm also going to make a thread where I'll be giving out 12 Haloween themed sigs, if you'd like one, just ask for one in
the thread.