code: function disableContextMenu() {
      // for now just images.
      Array.prototype.forEach.call(document.getElementsByTagName("img"), function(img) {
        img.addEventListener('contextmenu', preventEvent, false);
      });
    }
docs: Disable the context menus!
  At least on Android if you long press on an image it asks if you
  want to save it. I'd think "user-select: none" CSS should handle that
  but nope