If I put:

body {
background-image: url(bg.gif);
background-repeat: repeat-x;
margin: 0px;
width: 100%;
height : 100%;
}

In a CSS file, and call to the CSS file from index.html, will it automatically use it, or do I have to call for the specific "body" part?

Thanks.

it will use the whole thing

Alright sweet. Thanks again.