code: function loadImage ($imageElement, newSource, callback) {
          $imageElement.fadeOut(function () {
              $imageElement.attr("src", newSource);
              imgLoad($imageElement, function () {
                  $imageElement.removeClass("loading");
                  $imageElement.fadeIn();
                  if (typeof callback === "function") {
                      callback();
                  }
              });
          });
      }
docs: Load the image at the URL `newSource` in the `$imageElement` jQuery
  element with a fade in/out animation, then call the `callback`.
  @param {jQuery} $imageElement
  @param {String} newSource
  @param {Function} callback