image1 = new Image();
image1.src = "images/button_01_on.jpg";
image2 = new Image();
image2.src = "images/button_02_on.jpg";
image3 = new Image();
image3.src = "images/button_03_on.jpg";
image4 = new Image();
image4.src = "images/button_04_on.jpg";
image5 = new Image();
image5.src = "images/button_05_on.jpg";