How to organise photos by person, privately

Organising photos by person is the most useful thing a photo app can do. "Every photo of Mum", "the kids with their cousins", "me and Sam on holiday": that's how people actually look for photos. But grouping faces means making face data about everyone in your library, including people who never agreed to be in an app. This article explains how to organise photos by person while keeping control of that data, using the Photohawk app as the example.

Three ways to organise by person

By hand. Albums named after people, filled one photo at a time. Private, but slow, and it never keeps up.

In the cloud. Some services upload your whole library and group faces on their servers. Convenient, but your photos and the face data about everyone in them sit with someone else.

On the phone. The phone finds and groups faces itself. Your photos stay where they are. This is how the iPhone's own Photos app works, and how Photohawk Family is built.

How on-device grouping works

When an app groups faces on the phone, three things happen:

1. Finding faces. Each photo is scanned for faces, on the phone.
2. Describing them. Each face becomes a face template, a set of numbers describing its features. It's not a picture of the face.
3. Grouping them. Templates that are similar enough are grouped into one person. You name the group, and corrections you make (merging two groups, taking a photo out) teach it.

Scanning a big library takes a while. The Photohawk app does it quietly, mostly while the phone charges.

Where cloud matching fits

Grouping on the phone alone is good, but the phone has limits: a big library, children who change fast, people who look alike. To group people more accurately, the Photohawk app offers cloud face matching, as a separate choice:

• Only small face cut-outs are sent, never your photos.
• They go to our secure cloud, run by Amazon Web Services, and that face data is only yours.
• It's a second consent, asked on its own screen: continue, or keep it on your phone only.
• Turn it off and the cloud copy is deleted. Your people stay on your phone.

If you'd rather nothing about faces leaves your phone, choose to keep it all on your phone. Grouping still works.

Consent that means something

Face data is biometric data, which privacy laws treat as especially sensitive. In the Photohawk app:

• Face grouping is off until you turn it on. The consent box starts unticked.
• Turning it off deletes your face data, on your phone and in the cloud.
• The face data on your phone isn't in your phone backups.
• Face grouping isn't offered to people who live in Illinois, because of that state's biometric privacy law.

Our article on face grouping and privacy explains each of these in more detail.

Names, circles and corrections stay with you

Organising by person is more than grouping. In the Photohawk app:

• Names you give people are stored on your phone.
• Circles, like "My family" and "Friends", are just for you. They're never sent anywhere, and you can search by them: "My family at the beach".
• Corrections always win. If you merge two groups or say a photo isn't someone, that sticks.

Find, then share

Once your photos are organised by person, you can search them the way you remember them, "Maya with a dog", and send people the photos they're in. Photos leave your phone only when you share them, and only the people you share with can see them. See sharing photos with the people in them.

A short checklist for any app

Whichever app you use to organise photos by person, ask:

• Are faces found on my phone, or are my photos uploaded?
• If anything is sent, what exactly, and is it a separate choice?
• Is face grouping off until I turn it on?
• What happens to face data when I turn it off or delete the app?
• Are there ads, or is my data used for anything else?

The Photohawk app has no ads. If you have children, our guide to finding every photo of your child on iPhone is a good next read.

Photohawk Family is coming soon to iPhone, with Android to follow. Keep an eye on photohawk.com for the launch.