function picmaxwah(obj,maxw,maxh){
	var strw = obj.width;
	var strh = obj.height;
	if ((strw <= 0) || (strh <= 0)) return false;
	
	if ( strw > maxh){
		obj.width = maxw;
		obj.height = strh * ( maxw / strw);
		}
		
  if ( strh > maxh ){
		obj.height = maxh;
		obj.width = strw * ( maxh / strh);
		}
		
	obj.alt = obj.width + "กม" + obj.height;
}