iOS 11 Memories Upgrades
Apple upgrades Memories in Photos so that you can now watch in landscape or portrait mode. This lets you see more of the memory, no matter how you watch it.
The iOS 11 update uses machine learning to pull out data about your photos to create more memories. This includes recognizing your pets, to create pet specific memories. The feature also pulls out birthdays and other events automatically to create new memories for you.
If you own the iPhone 7 Plus, you'll see better Portrait Mode images in memories thanks to optical image stabilization, Ture Tone Flash and HDR.