title: How know my UIImage is loaded on IOS ?
body: <p>this is my code to load my images.</p>
  
  <pre><code>NSString *urltest = test[@"images"][@"items"][i][@"url"];
      url = [NSURL URLWithString:urltest];
      data = [NSData dataWithContentsOfURL:url];
      img = [[UIImage alloc] initWithData:data];
  [self.imgView setImage:img];
  </code></pre>
  
  <p>I would like to know when my is loaded. How can i do that?</p>