title: Request NSPhotoLibraryAddUsageDescription permission
body: <p>I'm trying to save image to Photos app on iOS 10 and 11 versions. <a href="https://developer.apple.com/library/content/documentation/General/Reference/InfoPlistKeyReference/Articles/CocoaKeys.html#//apple_ref/doc/uid/TP40009251-SW73" rel="noreferrer">Therefore</a> on iOS 11 I need to request <code>NSPhotoLibraryAddUsageDescription</code> permission, on iOS 10 <code>NSPhotoLibraryUsageDescription</code>. </p>
  
  <p>As Apple documentation <a href="https://developer.apple.com/documentation/photos/phphotolibrary/1620736-requestauthorization?language=objc" rel="noreferrer">claims</a>, <code>[PHPhotoLibrary requestAuthorization:]</code> obtains permission <strong>only</strong> for <code>NSPhotoLibraryUsageDescription</code> key.</p>
  
  <p>If you have both keys in <code>Info.plist</code> file and select "Add photos only" to Photos permissions in your app, <code>[PHPhotoLibrary authorizationStatus]</code> returns <code>PHAuthorizationStatusDenied</code>. </p>
  
  <p>Does anybody know how to deal with these permissions?</p>