1. Find an image you want to use, preferably a picture that isn't huge.
2. Host (upload) the picture somewhere. Like Imagecave.com, Photobucket.com, or wherever else. (These sites require signing up, some don't though.) I use Imagecave.
3. After hosting the picture, look for a link associated with the image that looks like this
Code: Select all[img]http://www.imagecave.com/username/blah_blah_blah.jpg[/img]
4. Copy everything in that link including both of the [img] tags at the beginning and end of the link.
5. Edit your signature and paste your link there, save your signature.
6.????
7.PROFIT!