var siteRoot = "./_images";

function preLoad() {
if(document.images) {
  img1= new Image();
  img2= new Image();
  img3= new Image();
  img4= new Image();

  img1.src=siteRoot+"/btn-about-ov.gif";
  img2.src=siteRoot+"/btn-contact-ov.gif";
  img3.src=siteRoot+"/btn-community-ov.gif";
  img4.src=siteRoot+"/btn-models-ov.gif";
}
}

function over(img_name,img_src) {
 document[img_name].src=siteRoot+"/"+img_src;
}
function out(img_name,img_src) {
 document[img_name].src=siteRoot+"/"+img_src;
}