function preload_images()
{
    if (document.images) {
        var args = preload_images.arguments;
        for (var i = 0; i < args.length; i++) {
            preload_image(args[i]);
        }
    }
}

function preload_image(src)
{
    if (!document.preloaded) {
        document.preloaded = new Array();
    }
    var i = document.preloaded.length;
    document.preloaded[i] = new Image;
    document.preloaded[i].src = src;
}

function image_over(id, src)
{
    if (document.images) {
        if (document.images[id]) {
            var i = document.images[id];
        } else if (document.getElementById) {
            var i = document.getElementById(id);
        }
        if (i.old_src == null) {
            i.old_src = i.src;
        }
        i.src = src;
    }
}

function image_out(id)
{
    if (document.images) {
        if (document.images[id]) {
            var i = document.images[id];
        } else if (document.getElementById) {
            var i = document.getElementById(id);
        }
        i.src = i.old_src;
    }
}