Photos: Move images from iCloud to local storage without losing metadata (albums, tags, etc)?
Assuming your photo library is complete (&quot;Download Originals&quot; is checked), I'd recommend the following process:

Close out Photos
In Finder, navigate to the Photos library (~/Pictures/Photos Library.photoslibrary)
Duplicate the library (Right click &gt; Duplicate), then open it by double clicking

This shouldn't double the amount of space used by the device since the system will link the original files together until one is modified


You will be able to confirm disconnection from iCloud.
Delete photos from the non-iCloud copy that you want to keep in iCloud.
Delete photos from the iCloud copy that you want to keep local only.
Empty the recently deleted on the local copy to save space

Unfortunately, you cannot repeat this process and merge local libraries. If this is for archival purposes, I'd recommend planning on using a new target library for each period of time or event you're archiving.