(Creating styles) Background Image Question

[HMBeaty]

Hopefully this is something simple, but I'm playing around with some different style customizations and am curious to if the background image can be "stretched" to fit the members/users screen. Right now, I'm using images with a dimension of 1600x900 and obviously, on small resolution screens, some of that image would get cut off. So, is this possible to do? If so, how would I go about editing this?

--------------- Added [DATE]1305474564[/DATE] at [TIME]1305474564[/TIME] ---------------

Ok, I THINK I've basically narrowed it down to this:

.XXXXXXX
{
    background-image:url('images/mybgimage.jpg');
    width: 100%;
    position: absolute;
    top: 0;
    left: 0;
}

But how do I get it to work with the stylevar doc_background? Anyone know?