title: How to async load images on dynamic UITableView?
body: <p>Now I have a custom cell with the image and label. Later I print these cells by:</p>
  
  <pre><code>func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -&gt; UITableViewCell {
  
      let cell:customCell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as! customCell
  
      var url = NSURL(string: postCover[indexPath.row])
  
      if let data = NSData(contentsOfURL: url!) { 
          cell.cellImage.image = UIImage(data: data)
      }
  
      var title = postTitle[indexPath.row]
  
      cell.cellLabel.text = title
  
      let indexPath = tableView.indexPathForSelectedRow()
  
      return cell
  }
  </code></pre>
  
  <p>and when I open an app and scroll it freezes. How can I fix this bug?</p>
  
  <p>I read about it, that I must use async image loading in my tableView, but don't I load them async already?</p>
  
  <p>I searched and think about it 4-5 days and nothing. Can anyone give me some tips, please?</p>