title: How to define maximum width constraint with Auto-Layout?
body: <p>A <code>UIImageView</code> is added to a <code>UITableViewCell</code> using Auto-Layout.</p>
  
  <p>The width of the <code>UIImageView</code> should be 50% of the width of the <code>UITableViewCell</code> but in any case not larger than 50px.</p>
  
  <p>This does not work:</p>
  
  <pre><code>    NSLayoutConstraint.activate([
          cellImageView.topAnchor.constraint(equalTo: contentView.topAnchor),
          cellImageView.bottomAnchor.constraint(equalTo: contentView.bottomAnchor),
          cellImageView.centerXAnchor.constraint(equalTo: contentView.centerXAnchor),
          cellImageView.heightAnchor.constraint(equalTo: cellImageView.widthAnchor, multiplier: cellImage.size.height / cellImage.size.width),
          cellImageView.widthAnchor.constraint(equalTo: contentView.widthAnchor, multiplier: 0.5),
          cellImageView.widthAnchor.constraint(lessThanOrEqualToConstant: 50)
          ])
  </code></pre>
  
  <p>How do I have to define the layout constraints?</p>