rolls_local = new Array (1);
rolls_local[0] = new Image(); rolls_local[0].src = "img/bul.gif";

ups_local = new Array (1);
ups_local[0] = "img/bul_ml.gif";
function swapLocal(img,swp) {
       document.images[img].src = rolls_local[swp].src;            
}
function swapBackLocal(img,swp) {
       document.images[img].src = ups_local[swp];          
}