var image1 = new Image(800,550);
image1.src = "images/background.gif";
var image2 = new Image(135,30);
image2.src = "images/home_over.gif";
var image3 = new Image(135,30);
image3.src = "images/about_over.gif";
var image4 = new Image(135,46);
image4.src = "images/psycho_over.gif";
var image5 = new Image(135,32);
image5.src = "images/qual_over.gif";
var image6 = new Image(135,30);
image6.src = "images/contact_over.gif";


function roll(img_name, img_src)
   {
   document[img_name].src = img_src;
   }