ith the
  // dimensions of the image, pointing the `data-url` link
  var on_click = function (e) {
    var d = e.target.dataset || {};
    if (d.url) {
      // Add some extra height for the modebar
      var height = 'height=' + (e.target.clientHeight * 1.05);
      var width = 'width=' + e.target.clientWidth;
      var param = 'location=yes,' + height + ',' + width + ',scrollbars=yes,status=yes';
      window.open(e.target.dataset.url, '_blank', param);
    }
  };

  var on_hover = function (e) {
    var 