if (document.images) {

   imgs0on = new Image(17,17);
   imgs0on.src = "/images/arrow_green_big_on.gif";

   imgs0off = new Image(17,17);
   imgs0off.src = "/images/arrow_green_big_off.gif";

   imgs1on = new Image(17,17);
   imgs1on.src = "/images/arrow_green_big_on.gif";

   imgs1off = new Image(17,17);
   imgs1off.src = "/images/arrow_green_big_off.gif";

   imgs2on = new Image(17,17);
   imgs2on.src = "/images/arrow_green_big_on.gif";

   imgs2off = new Image(17,17);
   imgs2off.src = "/images/arrow_green_big_off.gif";

 }

 function changeImages() {
   if (document.images) {
     for (var i=0; i<changeImages.arguments.length; i+=2) {
       document[changeImages.arguments[i]].src = eval(changeImages.arguments[i+1] + ".src");
     }
   }
 }