function newImage(imgSrc) {

    var imgName = new Image();
    imgName.src = imgSrc;

    return imgName;

}

function change(imgName, imgLocation) {
    document[imgName].src = imgLocation;
}

var preloadFlag = false;
function loadImages() {
    if (document.images) {
        home_over = newImage("img/Button_Home_Rollover.gif");
        profile_over = newImage("img/Button_Profile_Rollover.gif");
        gallery_over = newImage("img/Button_Gallery_Rollover.gif");

        preloadFlag = true;
    }
}