Your photos survive a lost phone, but not a wrong tap

Drop your phone in a lake and your photos are fine. Hand that same phone to a grandchild who taps the wrong thing and they can vanish from every device you own. The cloud is syncing your photos rather than backing them up.

Sync means there is one library and every device is a window onto it. Not a copy on the phone and a spare in the cloud — one set, displayed in several places. Add something, edit something or delete something and the change travels everywhere within seconds. The system has no way to tell a good decision from a bad one.

Apple is blunt about this. Delete a photo on one device and it is deleted everywhere iCloud Photos is turned on, recoverable from a Recently Deleted folder for 30 days and permanently gone after that. Those same pages note something most people would find surprising: photos in iCloud Photos are not included in your iCloud backup, and Apple advises keeping separate copies.

Google Photos behaves the same way with different numbers. Deleted items sit in the trash for 60 days rather than 30, and anything deleted inside the app disappears from every device signed in. Google's free 15 gigabytes is also shared across Gmail, Drive and Photos, so a growing photo library can fill up an email account. When that happens, according to Google's help pages, incoming mail is refused and bounces back to the sender with a delivery failure notice.

OneDrive, Dropbox and Samsung Cloud follow the same pattern.

Deleting photos is one of the main ways to save cloud storage space. On Apple devices, deleted photos live in Recently Deleted (photos>utilities) album for 30 days. You need to delete them from that album to save space immediately.