Photos
How can I delete photos off my phone but keep. them on my MacBook?
MacBook Air 13″, macOS 10.14
Question marked as
Top-ranking reply
They'll only be deleted off your mac if both the phone and mac are syncing with iCloud. So to keep them on the mac, you need to disconnect either your mac, or your phone from iCloud.
If you still want to use iCloud to sync your devices, you can select optimise phone storage on the phone, and then it will only keep full size originals in iCloud. This will reduce the space taken on your phone to around 20% of the full library - but in this case you'll still need to keep all (optimised) photos on your phone.