if (document.images) {
   img0 = new Image(); img0.src = "image/navi_index1b.gif";
   img1 = new Image(); img1.src = "image/navi_index2b.gif";
   img2 = new Image(); img2.src = "image/navi_index3b.gif";
   img3 = new Image(); img3.src = "image/navi_index4b.gif";
   img4 = new Image(); img3.src = "image/navi_index5b.gif";
   img5 = new Image(); img4.src = "image/navi_index6b.gif";
}
function setImage(img, image) {
   if (img) {
      img.src = image;
   }
}