Check Photo gallery is accessible or not iphone

Check Photo gallery is accessible or not iphone

I am accessing the photo gallery using below code :
UIImagePickerController* picker = [UIImagePickerController new];
picker.sourceType = type;
picker.mediaTypes =
[UIImagePickerController availableMediaTypesForSourceType:type];
picker.delegate = self;
[self presentViewController:picker animated:YES completion:nil];
So I user open Gallery for first time then application is display popup
like this :

If user select the OK then its work fine. But if user select the Don't
Allow then photo gallery is not able to access from application. My
question is if user open Photo Gallery then how to check whether photo
gallery is accessible or not.
Thanks,