Are hidden photos saved to iCloud?

Yes, if iCloud Photos is on. Apple says that when you use iCloud Photos, photos you hide on one device are hidden on your other devices too, which means the hidden photo is part of the library that syncs. Hiding changes where a photo appears in Photos. It does not change where the photo is stored.

How it works

iCloud Photos keeps your library in iCloud so you can reach it from other devices, and Apple says changes you make on one device change on your others. Hiding is one of those changes. A photo you hide on your iPhone becomes hidden on your iPad or Mac signed in to the same account. The hidden photo is still uploaded, at full resolution, as part of the library.

Apple also says hidden items do not appear anywhere else in Photos, such as the Library or other albums. That describes what you see on screen, not what is stored in iCloud.

How to check whether iCloud Photos is on

On an iPhone, open Settings, tap your name, tap iCloud, then tap Photos. Apple's restore guidance says that if "Sync this iPhone" is on, your photos are stored in iCloud Photos. If it is off, photos on this iPhone are not being synced from here.

What you can do

  1. Decide whether you are happy for these photos to be in iCloud. If you are, the Hidden album is a reasonable way to keep them off the main grid.
  2. If you are not, do not rely on hiding. Turning off syncing on one device stops new changes crossing between that device and the others, but read how to stop iCloud Photos syncing to other devices first, because photos already uploaded stay in iCloud.
  3. For photos that must stay off iCloud, keep them in a separate store from the start. Deleting a photo with iCloud Photos on deletes it on every device, so check delete photos from iPhone but keep them in iCloud before you move anything.

What this does not cover

Turning off the Hidden album's visibility in Settings does not stop syncing. A vault app does not remove photos that were already uploaded. And hiding is not encryption; for what Apple can read, see can Apple see your hidden photos.

SituationWhat happens to a hidden photo
iCloud Photos onUploaded and synced; hidden on your other devices too
iCloud Photos off on this iPhoneNot synced from this iPhone
You turn off "Show Hidden Album"Still stored and synced; just not visible in Photos
You import it into a vault appThe vault copy is separate; any uploaded copy stays until you delete it

For the bigger picture, see is the Hidden album secure, the short answer do hidden photos sync to iCloud, and Hidden album or vault app.

Frequently asked questions

Do hidden photos sync to my iPad?

With iCloud Photos on, yes. Apple says photos you hide on one device are hidden on your other devices.

Does hiding a photo keep it out of iCloud?

No. Hiding only changes where it appears in Photos.

How do I see if iCloud Photos is on?

Settings, your name, iCloud, Photos. If "Sync this iPhone" is on, your photos are stored in iCloud Photos.

Will a vault app remove photos already in iCloud?

No. Delete the original deliberately, after checking what deleting does on your devices.

Sources

StrongRoom is a free iPhone app, coming to the App Store.

Free for iPhone. Pro is optional. What Pro changes.

Coming to the App Store. See what version 1.0 includes.