var preloaded = [];

  for (var i = 1; i <= 6; i++) {
   preloaded[i] = [loadImage(i + "-0.gif"), loadImage(i + "-1.gif")];
  }

  function init() {

   if (mtDropDown.isSupported()) {
    mtDropDown.initialize();

    //menu1.onactivate = function() { swapImage("button1", preloaded[1][1].src) };
    //menu1.ondeactivate = function() { swapImage("button1", preloaded[1][0].src) };

    //menu2.onactivate = function() { swapImage("button2", preloaded[2][1].src) };
    //menu2.ondeactivate = function() { swapImage("button2", preloaded[2][0].src) };

    //menu3.onactivate = function() { swapImage("button3", preloaded[3][1].src) };
    //menu3.ondeactivate = function() { swapImage("button3", preloaded[3][0].src) };

    //menu4.onactivate = function() { swapImage("button4", preloaded[4][1].src) };
    //menu4.ondeactivate = function() { swapImage("button4", preloaded[4][0].src) };

    //menu5.onactivate = function() { swapImage("button5", preloaded[5][1].src) };
    //menu5.ondeactivate = function() { swapImage("button5", preloaded[5][0].src) };

    //menu6.onactivate = function() { swapImage("button6", preloaded[6][1].src) };
    //menu6.ondeactivate = function() { swapImage("button6", preloaded[6][0].src) };
   }
  }

  function loadImage(sFilename) {
   var img = new Image();
   img.src ="images/" + sFilename;
   return img;
  }

  function swapImage(imgName, sFilename) {
   document.images[imgName].src = sFilename;
  }