code: function (format, callbackFn) {
                      var self = this,
                          args =
                              [
                                  format
                              ],
                          url = this.options.hostAndPort + '/page/functions/renderBase64';
                      this.options.debug && console.log('calling execute method  for %s and with %d params: %s'.grey, url, args.length, JSON.stringify(args));
  
                      request.post(url, {form:{ args:JSON.stringify(args)}},
                          function (error, response, body) {
                              error && console.error(error);
                              if (response && response.statusCode === 200) {
                                  callbackFn && callbackFn.call(self, body);
                              }
                              else {
                                  console.log('error in response %s'.red.bold, body);
                                  callbackFn && callbackFn.call(self, false, body);
                              }
                          });
                      return this;
                  }
docs: Renders the web page to an image buffer and returns the result as a base64-encoded string representation of that image. Supported formats are PNG, GIF, and JPEG.