If you have an image, and you want to use it, fixed in place, as the background for your site (a-la the little green guy in the body of
NZ Android Forums - The Front Page), it's quite easy.
First, prepare your image. You probably want to make it around 1024x768, as this is about the minimum resolution people are browsing on. Upload it to somewhere you can remember the path.
Then, in the Style Manager for your style, go to Stylevars, then body_background, in the Common section.
Enter into the Background Image area this:
PHP Code:
url(http://path/to/image) fixed center
It may also pay to change the Background Color to match your image.
