var aryImages = new Array(8);

  aryImages[0] = "img/menu/esittely_on.jpg";
  aryImages[1] = "img/menu/hinnasto_on.jpg";
  aryImages[2] = "img/menu/varaa_on.jpg";
  aryImages[3] = "img/menu/yhteys_on.jpg";
  aryImages[4] = "img/menu/yhteydet_on.jpg";

  for (i=0; i < aryImages.length; i++) {
    var preload = new Image();
    preload.src = aryImages[i];
  }

  function swapImageOn(imgIndex) {
    switch (imgIndex) {
      case 1:
       document.img1.src = aryImages[0];
       return;
      case 2:
       document.img2.src = aryImages[1];
       return;
      case 3:
       document.img3.src = aryImages[2];
       return;
      case 4:
       document.img4.src = aryImages[3];
       return;
      case 5:
       document.img5.src = aryImages[4];
       return;
    }
  }

  function swapImageOut(imgIndex) {
    switch (imgIndex) {
      case 1:
        document.img1.src = "img/menu/esittely.jpg";
	return;
      case 2:
        document.img2.src = "img/menu/hinnasto.jpg";
	return; 
      case 3:
        document.img3.src = "img/menu/varaa.jpg";
	return; 
      case 4:
        document.img4.src = "img/menu/yhteys.jpg";
	return; 
      case 5:
        document.img5.src = "img/menu/yhteydet.jpg";
	return; 
   }
  }