if (document.images) {
  var arrowoff = new Image(12,12); arrowoff.src = "/img_new/arrow_0.gif";
  var arrowon = new Image(12,12); arrowon.src = "/img_new/arrow_1.gif";
}

function change(img3Name) {
  if (document.images) document[img3Name].src = eval('arrowon.src');
}
function release(img3Name) {
  if (document.images) document[img3Name].src = eval('arrowoff.src');
}