title: UIImagePNGRepresentation issues? / Images rotated by 90 degrees
body: <p>I want to load images from UIImagePickerController, then save the selected photo to my app's document directory.</p>
  
  <pre><code>UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage];
  NSData *data1 = UIImagePNGRepresentation(image);
  
  NSString *fileName = "1.png";
  NSString *path = //get Document path, then add fileName
  BOOL succ = [data1 writeToFile:path atomically:YES];
  </code></pre>
  
  <p>but after I save the image to my document, I found that, the image was rotated 90 degree, then I change the method UIImagePNGRepresentation to UIImageJPEGRepresentation, this time it's fine, anyone know what's the problem?</p>