September 7, 2026
"Your library stays in sync across devices" sounds great and vague. Here's the concrete mechanism, the honest limits, and what it takes for it to work for you.
Sync doesn't happen between your phones directly. There's no phone-to-phone handshake involved. Instead, each device talks to the same cloud library: a photo uploaded from phone A is stored there, and when phone B signs in and refreshes, it reads from that same library. Both devices are clients of one source of truth.
It's why sync survives a lost or replaced phone — a phone isn't in the chain, it's just one client. It's also why losing a device doesn't lose your library: the copy in the cloud outlives whichever device you happen to hold. This is the whole reason backup and sync are the same infrastructure.
If a photo is missing on another device, the most common causes are simple: the upload hadn't finished yet, background activity is restricted on the phone that took the photo, or you're looking at a device that isn't signed in. The support page walks through each fix.
Uploads from each device are encrypted in transit during sync, and we're explicit that we don't claim at-rest or end-to-end encryption. Read the nuance in our encryption explainer.