theImages  = new Array("menu-html2.gif", "menu-basics2.gif", "menu-tags2.gif", "menu-links2.gif", "menu-imagess2.gif", "menu-lists2.gif", "menu-tables2.gif", "menu-frames2.gif", "menu-forms2.gif", "menu-colors2.gif", "menu-advanced2.gif", "menu-toxicbug2.gif");
preloadImg = new Array(theImages.length);
for (i=0; i<theImages.length; i++) { preloadImg[i] = new Image(); preloadImg[i].src = theImages[i]; }

function swap(ver, name) {
 var imgname = "menu-" + name + ver + ".gif";
 document.images[name].src = imgname;
}