title: how to make a simple multithreading?
body: <p>Okay, now I was making a mobile application like restaurant finder, I want to show a photo of the restaurant</p>
  
  <p>the example : <code>restaurant x &lt;image x&gt;</code></p>
  
  <p>It's a code:</p>
  
  <pre><code>if (ImageToDisplay != nil)
  {
     NSData * imageData = [[[NSData alloc] initWithContentsOfURL: [NSURL URLWithString: ImageToDisplay.URL]]autorelease];
     ImageForRestaurant.image = [UIImage imageWithData: imageData];
  }
  </code></pre>
  
  <p>The problem is this process of downloading pictures may take too long. So I want the process to be run on a different thread.</p>
  
  <p>That way the code after that can run without having to wait this one to finish.</p>
  
  <p>How can I do so?</p>