title: Swift: UIImageView - Unexpectedly found nil while unwrapping an Optional value
body: <pre><code>class DisplayImageVC: BasePageView { //BasePageView inherits from UIViewController
  
      @IBOutlet weak var displayImage: UIImageView!
          override func viewDidLoad() {
          self.displayImage.backgroundColor = UIColor.yellowColor()
      }
  </code></pre>
  
  <p>....</p>
  
  <p>in another class I try this and get a fatal error:</p>
  
  <pre><code>    var displayImageView = self._pageContent[1] as DisplayImageVC        
      displayImageView.displayImage.image = UIImage(named: ("displayChecklane"))
  </code></pre>
  
  <p><strong>Log:</strong></p>
  
  <pre><code>fatal error: unexpectedly found nil while unwrapping an Optional value
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/bEohB.png" alt="enter image description here"></p>
  
  <p>Images.xcassets
  <img src="https://i.stack.imgur.com/G3QWo.png" alt="enter image description here"></p>