title: Why image downloading in Groupon ios app is fast?
body: <p>I am doing the ios app like groupon, where i am constructing the images with NSData dowloaded in background with</p>
  
  <pre><code>[NSData dataWithContentsOfURL:myURL]
  </code></pre>
  
  <p>in my tableView. But relatively its slower than groupon. What all techniques I can implement to make it faster. And also are there any caching techniques/frameworks I can implement after downloading? </p>