function loadImage(sFile)
{
  var oImg=new Image();
  oImg.src="button/"+sFile;
}

function preloadImages()
{
  document.forms[0].sSearch.focus();
  loadImage("zoek-over.jpg");
  loadImage("home-over.jpg");
  loadImage("info-over.jpg");
  loadImage("series-over.jpg");
  loadImage("collecties-over.jpg");
  loadImage("nieuwestrips-over.jpg");
  loadImage("activiteiten-over.jpg");
  loadImage("links-over.jpg");
}

function changeImage(sName,sFile)
{
  document.images[sName].src="button/"+sFile;
}