I am wondering if someone, could please tell me if there is a way to make a background image resize for different screen resolutions without JavaScript, making it cross-browser? Thanks in advance.
Not with current CSS, but CSS3 (which works in some browsers) will have more options. For example, read this:
A List Apart: Articles: Supersize that Background, Please!
and see this example linked to that article:
CSS2 background 1280x960 center center fixed, CSS3 background-size contain