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