To change the large Banner on the Front of your site follow the instructions below
Create an ftp account in your cpanel - for instructions on how to do this click here
You will then need an ftp programme - open your connection.
public_html (if you are on our server you will not need this go straight to template)
Choose a Theme you wish to change
header.gif - Transfer this over to your desktop (do not change the name of this file)
Your new header must be the same size as the original (675 x 233 pixel)
Transfer this back onto your site via your ftp programme