CSS Tricks
Non-Tiling Background Image:
Here is the CSS code to add a background image that won't tile. Place this CSS code between the <head> and </head> tags. Add a background color too for those who can't see the image.
<style type="text/css"> <!-- BODY { background: #ffffff url(filename.gif) no-repeat } --> </style>
You can "center" the background image on the web page but it will not stretch the image out to fill the full screen.
<style type="text/css"> <!-- BODY { background: #ffffff url(filename.gif) no-repeat center } --> </style>