function resize(which, max) 
{
   var elem = document.getElementById(which);
   if (elem == undefined || elem == null) return false;
   if (max == undefined) max = 100;
   if (elem.width > elem.height) 
   {
   if (elem.width> max) elem.width = max;
   } 
   else 
   {
   if (elem.height> max) elem.height = max;
   }
}