code: function(eventEmitter, access_token, bot_id, picture_url) {
  
    API.Bots.post(
      access_token,
      bot_id,
      "Picture Message Test",
      {picture_url:picture_url},
      function(err,ret) {
        if (err) {
          eventEmitter.emit('error', err);
        } else {
          eventEmitter.emit('success', ret);
        }
      });
  
    eventEmitter.emit('start');
  
    return eventEmitter;
  
  }
docs: **********************************************************************
  Helper function for posting a picture message
  *********************************************************************