function preload(name, first, second)
{ pics[objCount] = new Array(3);
  pics[objCount][0] = new Image();
  pics[objCount][0].src = first;
  pics[objCount][1] = new Image();
  pics[objCount][1].src = second;
  pics[objCount][2] = name;
  objCount++;
}
function on(name)
{ for (var i = 0; i < objCount; i++)
  { if (document.images[pics[i][2]] != null)
      if (name != pics[i][2])
        document.images[pics[i][2]].src = pics[i][0].src;
      else
        document.images[pics[i][2]].src = pics[i][1].src;    
  }
}
function off()
{ for (var i = 0; i < objCount; i++)      
    if (document.images[pics[i][2]] != null) 
      document.images[pics[i][2]].src = pics[i][0].src;
}