You'll have to upload your banner (saved as a .jpg file) to an Internet storage site first -
www.photobucket.com is a good free one - and then get the URL, which will look something like this (my current banner):
http://img.photobucket.com/albums/v6.../VEBanner1.jpg
Then go to your Profile page and insert the URL of your banner between [img] and [/img] ... no spaces! and it SHOULD show up.
Good luck!
