$(function () {
        var image_cache = new Object();
        $("img,input[type=image]").not("[src*='_on.']").each(function () {
                var imgsrc = $(this).attr("src");
                var imgsrc_ov = imgsrc.replace('_of.','_ov.');
                image_cache[this.src] = new Image();
                image_cache[this.src].src = imgsrc_ov;
                $(this).hover(function () {
                        this.src = imgsrc_ov;
                }, function () {
                        this.src = imgsrc;
                });
        });
});