Apple Photos and Time Machine question

step 1. I recommend another hard drive. 1. This will let you continue to fully use the photos library, just on an external instead of the computer’s drive. 2. I don’t like to manipulate things on a TM drive except with TM itself

step 2. once you’ve moved into the new computer, enter time machine and navigate to the picture folder and find the photos library. Select it to restore...you’ll be asked where to put it. Point to the external hard drive.

step 3. Now double click on the photos library on the external drive to open Photos with the library on the external.

step 4. Select the photos you want on the internal. Export them. Either to a temp folder on the computer or external. Quit photos. Now find the photos library on the computer and double click to open photos with the internal photos library. Import the photos in the temp folder. Remove the temp folder.

I'll answer this two ways:

1. Unless you configured TimeMachine to ignore your Pictures folder, your TM backup will contain your Photos library and you'll be able to copy it to another external drive and continue to add pictures to it. And yes, you can keep a small selection of photos on your MBP.
2. If you are willing to spend a few dollars on a monthly iCloud subscription you can put all your photos on iCloud. Photos has a nice feature found in Photos Preferences called Optimize Mac Storage. If you select this, your photos will be synced to your iCloud account in full size. Once synced, your MBP will retain just a thumbnail of the photo. As long as you are connected via WiFi you can pull any photo back into the computer to be edited or otherwise used. And when done it will be resynced if need be, and replaced with a thumbnail. This was my chosen route and it lets me take my thousands of photos everywhere without taking up huge amounts of drive space.