Hi. Making a sig with images requires a bit of knowledge of vB code. It's similar to html. Here's the help page.

The good news is that you can copy your [ img ] link right from the gallery. Upload your image, then go back to the page where your image is. The forum won't take you there automatically, you have to click your way back to "my gallery". A few lines below your image, it will say, "vb code: [ img ]http://(etc)[/ img ] Just copy and paste that line into your edit signature box.

(Hmmm... I think I'm going to ask the webmaster if he can make the gallery browsing a little easier.)