You can choose to use either a basic color or an image for your website background.
The html code for website backgrounds is very simple. Below are two samples, the first is for a basic white background using a html color code.
<body bgcolor=white>
The following piece of code will use an image as your web page background. Depending on the site of the image, it will "tile" itself to fill the entire screen of the user.
<body background=filename.gif>
You can use either .gifs or .jpges for your html backgrounds.