Banner/logo/sigFirst off you will have to go to your profile and click the allow HTML tag, Also click the always show my sig box. HTML tags have also got to be enabled in Admin-Panel-General-Admin_configuration.
Then To place a logo/banner/sig in your profile you will need to Enter this code in the sig box.
[url=http://your url here][img] your image link here[/img][/url]
so it will look something like this
Just place it in your sig box in your profile.