iOS11부터 사진 저장할때는 plist에 key가 하나 더 필요하군요.

iOS11에서 plist에 NSPhotoLibraryAddUsageDescription 가 없을때 사진을 저장하려 하면 앱이 crash 한다는걸 이제 알았어요.

https://developer.apple.com/library/content/documentation/General/Reference/InfoPlistKeyReference/Articles/CocoaKeys.html#//apple_ref/doc/uid/TP40009251-SW73

NSPhotoLibraryAddUsageDescription (String - iOS) This key lets you describe the reason your app seeks write-only access to the user’s photo library. When the system prompts the user to allow access, this string is displayed as part of the alert.
This key is supported in iOS 11.0 and later.

후~ 문서를 더 꼼꼼히 봤어야 했나 봅니다… 으이구 애플…