I've been looking around for this solution for a while but haven't got any. e.g one solution is
self.navigationItem.setRightBarButtonItem(UIBarButtonItem(barButtonSystemItem: .Stop, target: self, action: nil), animated: true)
This code will add a button with "stop" image. Just like this, there are other solutions with "search, "refresh" etc. But what if I want to add a button programmatically with the image I want.