img_M0 = new Image ();
img_M0.src = "Home-1-M.gif";
img_M1 = new Image ();
img_M1.src = "Home-2-M.gif";
img_M2 = new Image ();
img_M2.src = "Book-1.gif";
img_M3 = new Image ();
img_M3.src = "Book-2.gif";
img_M4 = new Image ();
img_M4.src = "World-1-Sml.gif";
img_M5 = new Image ();
img_M5.src = "World-2-Sml.gif";

function switch_image_logo (img_nr, img_obj)
 {window.document.images[img_nr].src = img_obj.src;}