// Create image objects, preload all active and inactive images.
    icons_on = new Image();
    icons_on.src = "images/icons.gif";
    desktop_on = new Image();
    desktop_on.src = "images/desk.gif";
    info_on = new Image();
    info_on.src = "images/info.gif";
    home_on = new Image();
    home_on.src = "images/home.gif";

    icons_off = new Image();
    icons_off.src = "images/icon_roll.gif";
    desktop_off = new Image();
    desktop_off.src = "images/desk_roll.gif";
    info_off = new Image();
    info_off.src = "images/info_roll.gif";
    home_off = new Image();
    home_off.src = "images/home_roll.gif";
    
// Function that switches off rollover
function imgAct(imgName) {
    document[imgName].src = eval(imgName + "_off.src");
}
// Function that switches on rollover
function imgInact(imgName) {
    document[imgName].src = eval(imgName + "_on.src");
}