Personally, I am a fan of Google photos. You can easily back up photos from different devices to your Google Account by the app which you can get from the Play Store. It has a great free storage option and you can access your photos from when you need to via the app. It's really best to always have your photos backed up, just in case something happens (though fingers crossed it never will). It also means that you free up the storage space on your S7 and your tablet for other fun stuff.