$(document).ready(function() {
    $('a[href$="lightbox"]').attr("rel", "lightbox");
    var items = $('a[href$="lightbox"]');
    var i = 0;
    for (i = 0; i < items.length; i++) {
        items[i].href = items[i].firstChild.src;
    }

    $('a[rel="lightbox"]').fancybox();
});