function raiseImage(index)
{
  /*get the set of pictures on the page*/
  var pictures = document.getElementsByName("picture");

  /*find the largest zIndex*/
  var biggest = 0;
 
  for (i = 0; i < pictures.length; i++)
  {
    var zIndex = pictures[i].style.zIndex;
    if (!zIndex) zIndex = 2;
    var zNumber = parseInt (zIndex);
    if (zNumber > biggest)
      biggest = zNumber;
  }

  /*incrementing by just 1 doesn't seem to do the trick*/
  pictures[index].style.zIndex = biggest + pictures.length;
  
}