// preload images
var image0 = new Image();
image0.src = "images/btn-consensa.gif";
var image1 = new Image();
image1.src = "images/btn-nieuws.gif";
var image2 = new Image();
image2.src = "images/btn-guestbook.gif";
var image3 = new Image();
image3.src = "images/btn-links.gif";
var image4 = new Image();
image4.src = "images/btn-coaching.gif";
var image5 = new Image();
image5.src = "images/btn-downloads.gif";
var image6 = new Image();
image6.src = "images/btn-contact.gif";

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