image1 = new Image();
image1.src = "/images/btn-01-on.gif";

image2 = new Image();
image2.src = "/images/btn-02-on.gif";

image3 = new Image();
image3.src = "/images/btn-03-on.gif";

image4 = new Image();
image4.src = "/images/btn-04-on.gif";

image5 = new Image();
image5.src = "/images/btn-05-on.gif";