title: Add EXIF metadata to a UIImage
body: <p>I need to add EXIF metadata to a <code>UIImage</code> taken either from the camera or an album, then save the image to an album. How can I do this?</p>
  
  <p>To take the photo I use:</p>
  
  <pre><code>picker.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;
  picker.sourceType = UIImagePickerControllerSourceTypeCamera;
  </code></pre>
  
  <p>but I don't know how to add EXIF data.</p>