Save image to photo library using photo framework

All you need to do is trigger a creation request. As the error says, you can access the change request only inside the performChanges block.

So to save the image you would do something like this:

[[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
    [PHAssetChangeRequest creationRequestForAssetFromImage:[info valueForKey:UIImagePickerControllerOriginalImage]];
} completionHandler:^(BOOL success, NSError *error) {
    if (success) {
         NSLog(@"Success");
    }
    else {
        NSLog(@"write error : %@",error);
    }
}];

In case you need to do something with the placeholder of the newly created asset, you can access it inside the same performChanges block:

PHAssetChangeRequest *changeRequest = [PHAssetChangeRequest creationRequestForAssetFromImage:[info valueForKey:UIImagePickerControllerOriginalImage]];
PHObjectPlaceholder *assetPlaceholder = changeRequest.placeholderForCreatedAsset;

In Swift 3 I do this to save the video to the library.

if mediaType.isEqual(to: (kUTTypeMovie as NSString) as String) {
    if let videoURL = info[UIImagePickerControllerMediaURL] as? URL {
        PHPhotoLibrary.shared().performChanges({
            _ = PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: videoURL)
        }, completionHandler: { (success, error) in
            if success {
                print("ok")
                let videoData = NSData(contentsOf: videoURL)
                // use videoData here if needed...
                if let posterImage = self.firstFrame(videoURL: videoURL) {
                    self.imageView.image = posterImage
                }
                picker.dismiss(animated: true) { () -> Void in
                }
            } else {
                print(error?.localizedDescription)
            }
        })
    }
}