function initRollOverImages() {   
    var image_cache = new Object();   
    $(".rollover a img").not("[@src*='_on.']").each(function(i) {   
        var imgsrc = this.src;   
        var dot = this.src.lastIndexOf('.');   
        var imgsrc_on = this.src.substr(0, dot) + '_f2' + this.src.substr(dot, 4);   
        image_cache[this.src] = new Image();   
        image_cache[this.src].src = imgsrc_on;   
        $(this).hover(   
            function() { this.src = imgsrc_on; },   
            function() { this.src = imgsrc; }   
        );   
    });   
}   
$(document).ready(initRollOverImages);