Google photos is the best gallery app. I am now using lenovo vibe k5 note. When I got the phone there was no gallery app in it. There was only google photos in it. I was disappointed at first but as I started using the app it was pretty good. The app has a number of features in it. Backing up your photos for free is one of them. The app keeps getting better and better after every update. You can archive your photos, restore it even if you delete them. The app even recognizes faces and sorts them accordingly. These features makes it better than any other gallery app out there.