image1 = new Image();
image1.src = "images/button1_down.gif";
image2 = new Image();
image2.src = "images/button2_down.gif";
image3 = new Image();
image3.src = "images/button3_down.gif";
image4 = new Image();
image4.src = "images/button4_down.gif";
image5 = new Image();
image5.src = "images/button5_down.gif";