Technically this thread should go on the Assembly, but that's okay.
So what you do is click on "My Control Center" at the top of the page (but it's not visible when you're on a thread, like now). It'll take you to a screen with a list of stuff along the left. In that list, click on "Edit Signature"
On that page, there will be a box, similar to the one you type your posts in. To put a picture, you need a URL (I would suggest using Imageshack or Photobucket to get a URL for your picture if you don't have one). Then you go:
[img]url here[/img]
and then you hit the "Submit" and voila, you have a picture in your signature.
And yes, I know some of this might be extraneous information, but I didn't know how much you knew.
Well then, as I said, you'd have to get an account on photobucket or imageshack (both are free, so you don't have to worry about that) and upload your image.
