If I delete a photo on my phone, it will delete it from iCloud, which is fine, but will it delete the copy stored on my laptop?
No. Deleting a photo from ANY one device, deletes it from ALL devices and iCloud.
“When you edit photos on any device with iCPL enabled, the same edits (including deletions, additions, etc) are synced to ALL other iCPL-enabled devices, including iCloud itself. So, NO, you will not be able to delete the local copies.”
The best strategy to adopt is to:
- Enable iCPL on all your devices; this means everything is always synced and accessible everywhere;
- Set Photos on iPhone to keep an “optimized” library; this setting will reduce local storage space required on the phone;
- Set Photos on MacBook to copy all originals; this gives you quick access to all files and acts as a backup of what’s in iCloud;
Think of iCPL as the “master” library that has everything you want to keep, everything is at its full resolution, and acts to sync everything to everything.