uinavigationbar - set navigationBar background image in swift

Question

Code below is not working for me, can anyone help to figure it out what is wrong?

var image = UIImage(named: "10384605_10152519403846670_5189785375955620548_n.jpg") as UIImage

self.navigationController.navigationBar.setBackgroundImage(image , forBarMetrics:UIBarMetrics)

Answer 1

self.navigationController.navigationBar.setBackgroundImage(image, 
                                                   forBarMetrics: .Default)