If you are wanting to add a graphic to the background of your website there are two ways to achieve this - in
HTML or
CSS.
In
HTML you need to modify the body tag of your source code to the following (where background.jpg is the image you want to use):
<body background="background.jpg">
In
CSS you add the following to your style sheet:
body
{
background
-image: url("background.jpg");
}