Making sense of Photos - keep only recent photos on icloud

I said at first I like photos for the way it works. But the program has its limitations. It is all fine until half of your drive is full and you can't move the images on an external location.

you simply use a correct drive and run your Photos library on it again nothing else needed except a large enough disk drive - and for the third time it is trivial to move photos anyplace you want using the Photos application, File menu ===> export to the desired location

Using Lightroom I have no issue relinking moved folders.

No problem - again different programs have different capabilities and no program has every possible capability - use the program that you prefer - since you think LR is superior you certainly should be using it

I wonder if it is possible to merge libraries manually. I wonder how does PowerPhotos work.

You can not not make any changes of any sort manually to the Photos library, you must only use the Photos application to make changes to the Photos library and you can not merge libraries at all - you can mostly merge them (losing projects) using iCloud Photo Library and using export & import or PowerPhotos you can merge one version of the photos losing either the edits or keeping the edits and losing the ability to revert to the original -- Notes on Merging Photos Libraries

LN

And the system library can't be on an external drive so moving it is impossible as well.

That is a misunderstanding. The system library can be on an external drive. Just plug the drive in, before you launch Photos.

What you cannot do, is keeping the library on a NAS, any kind of network share. See: Move your Photos library to save space on your Mac - Apple Support

I bought my MacBook Pros with a 1TB internal drive, so my system photo library fits well onto the internal drive; my library has currently roughly 200GB. But the archive of all photos is on a 3TB external drive, that I only plug in, when I need to look up photos that are not I my favorites collection.

Only the system library is synced to iCloud Photo Library - set the one you want as the system Library

to move photos between libraries either export from one and import to the other or us PowerPhotos

LN

Photos works just fine - PowerPhotos is a program by a third party which provides additional capabilities as do hundreds of other third party programs - no single program is ever going to do everything each and every person wants hence the free market lets third parties make money by developing programs to provide additional features for people who want them

to move photos between libraries either export from one and import to the other or use PowerPhotos

And of course as posted exporting form one library and importing into the other is an option requiring no third party software - nothing is required, just available if you want - one or the other, you choose to purchase PowerPhotos or to do it with Photos

LN

I wonder if it is possible to merge libraries manually. I wonder how does PowerPhotos work.

PowerPhotos is a very versatile companion to Photos, but I use it mainly for browsing the library, not for merging.

Because Apple does not allow much access for external editors to the library, you can only move the original or the edited versions between libraries. If you want both, you have to move them separately. It will not be possible to keep the edited version and the original paired. The documentation for PowerPhotos is here: https://www.fatcatsoftware.com/powerphotos/Docs/index.html

You may want to test the free trial, before buying the application.

And you have the solution

If you choose to continue using Photos use two libraries (or use iCloud Photo Library with optimized photos) or choose a different photo manage that works like you want

Clear and simple - you choose what you want and do it

And the reason we keep discussing the same thing is that you keep posting the same question even though it has been answered over and over in this thread (and in others) - I am done here - bye

LN

I am simply using two Photos Libraries, a smaller one for the photos I want in iCloud and a larger archive on my external drive.