backgroundImages = new Array("/shop/images/layout2010/background1.png",
                             "/shop/images/layout2010/background2.png",
                             "/shop/images/layout2010/background3.png",
                             "/shop/images/layout2010/background4.png");

currentBackgroundImage = 0;

function preloadBackgroundImages() {
  backgroundImageObjects = new Array();
  for (var i = 0; i < backgroundImages.length; i++) {
    backgroundImageObjects[i] = new Image();
    backgroundImageObjects[i].src = backgroundImages[i];
  }
}

function rotateBackgroundImage() {
  currentBackgroundImage = (currentBackgroundImage+1) % backgroundImages.length;
  $('#hintergrundgrafik2').hide().css('background-image', 'url('+backgroundImages[currentBackgroundImage]+')');
  $('#hintergrundgrafik2').fadeIn(2000, function() {
    $('#hintergrundgrafik').css('background-image', $(this).css('background-image'));
    $(this).hide();
  });
}

function startBackgroundRotation() {
  rotateBackgroundImage();
  setTimeout(function() { startBackgroundRotation(); }, 20000);
}

setTimeout(preloadBackgroundImages, 1000);
setTimeout(startBackgroundRotation, 20000);