title: Display an image or UIImage with a plain CALayer
body: <p>I've often read that using a <code>CALayer</code> rather than a <code>UIImageView</code> is an performance boost when it comes to heavy image usage. That makes sense, because <code>UIImageView</code> causes 3 copies of the image in memory, which is needed for Core Animation. But in my case I don't use Core Animation.</p>
  
  <p>How can I assign a <code>UIImage</code> (or its image data) to a <code>CALayer</code> and then display it?</p>