title: swift UITableView lags with images
body: <p>I would like to show images in TableView so I created a custom cell</p>
  
  <pre><code>override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -&gt;
      UITableViewCell {
  
      let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as TableViewCell
  
      if let image =  UIImage(data: self.photos[indexPath.row].image) {
  
          if image.size.width &gt; image.size.height {
  
              tableView.rowHeight = view.bounds.width *  0.71
  
          } else { tableView.rowHeight = view.bounds.width *  1.22
  
          }
  
          cell.cellImage.image = image
      }
  </code></pre>
  
  <p>I had a problem how to adjust cell's height so for each image its calculated separately and I use clip subviews for ImageView.</p>
  
  <p>The problem is that when I start adding photos the scroll of table is very laggy :(
  Even when I remove cell's height calculation nothing's changed.</p>
  
  <p>Does Anyone has any idea how to make it smooth in Swift?</p>