title: Swift Image clicked Button not changing
body: <p>I have a button which is supposed to change image when it is clicked but for some reason it is not changing to the image set for the UIControlState.Highlighted state</p>
  
  <pre><code> override func viewDidLoad() {
      super.viewDidLoad()
      let versusButtonClickedImage = UIImage(named: "versus_button_cicked") as UIImage
      let versusButtonImage = UIImage(named: "versus_button") as UIImage
      versusButton.setImage( versusButtonImage, forState: UIControlState.Normal)
  
  
      versusButton.setImage(versusButtonClickedImage, forState: UIControlState.Highlighted)
  
  
  }
  </code></pre>