Use Hidden album:
Open Photos
Tap Library
Tap Albums
Open Hidden (if needed, scroll down to find it)
To hide: open a photo or select photos → tap Share → tap Hide
To unhide: open Hidden album → select photos → tap Share → tap Unhide
Use Recently Deleted to remove:
Open Photos
Tap Albums
Tap Recently Deleted
Select items → tap Delete All or Delete
Use Notes to store photos locked:
Open Notes
Create a new note
Tap the photo icon to add a photo
Tap the share/lock option → enable Lock Note
Authenticate with Face ID/Touch ID or passcode
Use Files app with locked container:
Open Files
Tap Browse
Create a new folder
Move photos into the folder
Use a third-party app or secure storage that supports locking if you need a locked container
Use third-party secure photo vault apps:
Install a photo vault app from the App Store
Import photos into the app
Enable Face ID/Passcode in the app
Follow the app’s option to remove or hide originals if available