Downloading all photos from iCloud Photo Library without Photos app I have an iCloud account with about 800 photos stored in iCloud Photo Library. I’m trying to move them to a Mac and delete them from iCloud in order to clear up space.

I tried to connect my Mac to iCloud Photo Library by going into the Photos app’s preferences; however it then asks me to upgrade to a paid iCloud storage tier because I have over 5GB worth of local images that Photos wants to sync to iCloud.

So I don't think using the Photos app is going to work for offloading pictures to a Mac.

I then logged in to the Photos app at iCloud.com. I was able to select and download individual images, but it won’t let me select more than one at a time, so I can’t download them all in bulk. Selecting the first image, holding down the ⇧ shift key, then selecting the last image causes only the last image to be selected.

I could click on all 800 images while holding the ⌘ cmd key, but that’s obviously very tedious.

What’s the most efficient way to download images from iCloud Photo Library to a Mac that can’t connect to iCloud Photo Library without upgrading to a paid plan?
I highly recommend ndbroadbent's fantastic Python program the icloud_photos_downloader project. The project repository can be found at his Github account: https://github.com/ndbroadbent/icloud_photos_downloader. 

There are some great instructions on installation and use in the project README. Once installed, you run the program to download all your photos to a directory called foto_folder; from the terminal 

./download_photos.py ../foto_folder 
    --username=myemail@email.com
    --password=myp@ss
    --size=original
    --download-videos

And viola, it does its magic.

I've also posted this answer here: https://apple.stackexchange.com/a/311787/271502