function gross(v_nr) {
var i;
var v_div;
var v_img;
        for (i=0; i<4 && document.getElementById("grimg"+i); i++ ) {
             v_div = document.getElementById("grimg"+i);
             v_img = document.getElementById("img"+i);
                if (i == v_nr) {
                   v_div.style.width = v_img.width+"px";
                   v_div.style.height = v_img.height+"px";
                   v_div.style.visibility = "visible";
                } else {
                   v_div.style.visibility = "hidden";
                   v_div.style.width = "0px";
                   v_div.style.height = "0px";
                }
        }
}