title: Set alpha for UIView/Image
body: <p>I have a table view with a label array and a UIView, with a UIImage array</p>
  
  <pre><code>var menuItems = ["News", "Programm"]
  var currentItem = "News"
  
  var menuImages: [UIImage] = [UIImage(named: "news.png")!, UIImage(named: "programm_100.png")!]
  </code></pre>
  
  <p>The text and its color of the label is set by:</p>
  
  <pre><code>cell.titleLabel.text = menuItems[indexPath.row]
  cell.titleLabel.textColor = (menuItems[indexPath.row] == currentItem) ? UIColor.whiteColor() : UIColor.grayColor()
  </code></pre>
  
  <p>Now I want the Images to appear a bit grey, too.
  I've tried to set it with <code>cell.titlePicture.alpha</code>.</p>
  
  <p>How can I set UIView's alpha denericly depending on the current item?</p>
  
  <p><a href="https://i.stack.imgur.com/UHK1N.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/UHK1N.png" alt="menu"></a></p>