Ok kids. The BBCODE for IMG has been removed from signatures. Too many people creating signatures that violate our size restrictions. Makes the community hard to read. That said, all users that have been active for a period of time, can put an image in their signature using the upload feature. It needs to be no greater than 600x150. Find these options under SETTINGS > EDIT SIGNATURE.
Then, once you've uploaded the picture, include [sigpic][/sigpic] in your signature text.