UI导航栏图像标题

您可以执行以下操作：

var titleView = UIImageView(image: UIImage(named: "nameOfTheImage.ext"))
self.navigationItem.titleView = titleView

为了使图像适合您要的尺寸，您必须进行以下操作：

var titleView : UIImageView
// set the dimensions you want here
titleView = UIImageView(frame:CGRectMake(0, 0, 50, 70))
// Set how do you want to maintain the aspect
titleView.contentMode = .ScaleAspectFit
titleView.image = UIImage(named: "nameOfTheImage.ext")

self.navigationItem.titleView = titleView