Just some background information on iCloud Photos: The Photos.app is managing your photos and videos in a Photos Library, the file you have seen in your Pictures folder. The Photos Library is a package containing several files, your original image files and videos, plus several database files describing the adjustments you applied, the metadata you added, the albums and folders, the editing history of all items in the library. Photos cannot work without using a photos library, even if you are using iCloud Photos.
Cloud Photos is a syncing service. The main purpose is to keep the local Photos Libraries on all your devices identical and in sync. when you work with your photos on any of your devices, the changes will sync to iCloud and from there the changes will be updated by iCloud across all your other devices. we are always working with our local version of the library, and iCloud Photos is taking care of the versions on our other devices and updating them. This way we can work with our photos even if we do not have an internet connection available temporarily.
If you are using iCloud Photos to save storage , you can use the "optimize Storage" feature pointed out by muguy.
Use iCloud Photos on Mac - Apple Support
But do not delete the Photos Library. Photos needs the library. With "Optimize Storage" it will shrink over time, but do not go away completely. The optimization is fully automatic. When other apps are needing storage on your device, iCloud Photos will remove some high resolution originals and replace them on your Mac be smaller, optimised version for browsing to free more storage. This way the library can shrink to roughly 10% of the size in iCloud.
To be able to see your photos again, do the following:
- Open Photos, if it is not running.
- Open the menu item "Photos > Settings (or Preferences on older system versions)" and click the "General" tab. Click "Use as system Photos Library".
- Now click the iCloud tab and enable the checkmark for "iCloud Photos", then the checkmark for "Optimize Mac Storage"
Photos will now be able to access your iCloud Photos again, but only download the smaller, optimized version. Your local photos library will start out as small as possible, fully optimized.
If this is still too large and you need to free more storage, you would have to move your Photos Library to an external drive, but that is not very convenient on a portable Mac to have external drives connected, when we are not sitting at a desk.
See: Move your Photos library to save space on your Mac - Apple Support
