There's some confusing things regarding the signatures so I thought I'd specify.
If you wish to have a signature displayed, you will need to use a URL. When you go to edit signature use the img tags like so [img]urltoyourphoto.com[ /img] (without spaces of course)
By default your automatically set to "Do not display signature" in your user CP. You can set this too display your signature. Your signature if chosen to be a picture will then be displayed in your post.
If you wish to have a signature displayed, you will need to use a URL. When you go to edit signature use the img tags like so [img]urltoyourphoto.com[ /img] (without spaces of course)
By default your automatically set to "Do not display signature" in your user CP. You can set this too display your signature. Your signature if chosen to be a picture will then be displayed in your post.