(function($) {
  var cache = [];
  // Arguments are image paths relative to the current page.
  $.preLoadImages = function() {
    var args_len = arguments.length;
    for (var i = args_len; i--;) {
      var cacheImage = document.createElement('img');
      cacheImage.src = arguments[i];
      cache.push(cacheImage);
    }
  }
})(jQuery);

$('document').ready(function () {
    // Preload

    $.preLoadImages(
        '/images/4dlogo_hover.png'
    ); 

    $('div.dlogo img').hover(
        function () {
            $(this).attr('src', '/images/4dlogo_hover.png');
        },
        function () {
            $(this).attr('src', '/images/4dlogo.png');
        }
    );

});