How do I backup or download my iCloud photos on usb

Download first the photos to the computer, see this Apple article: Download iCloud photos and videos

Download iCloud photos and videos - Apple Support

Then from the computer save the photos to an external hard drive.

You can’t do all of that without syncing iCloud to a Mac with the Photos app or Windows with iCloud for Windows. However, you can download just the photos by logging in to https://icloud.com/photos

You need to select photos to download before the download icon becomes active. Start with a few at a time; if that works, increase the number gradually.

I have several active computers and phones so there is no one central photo repository other than iCloud. I want to download a complete backup or archive of all my photos on iCloud with folders, edits, metadata directly onto an external drive, without risk of losing or changing anything in iCloud, or ending up with the partial library of photos on just one of my devices,

Thanks Lawrence. I don't have a HD in any of my laptops with enough free space for all these photos, movies etc. Can I just download all my photos via 'Library'? f not - do I piece them out by year or something? (I am also afraid of having whatever I download being removed from iCloud and becoming my new 'Library' of record )

Thanks Lawrence. I have like 100,000 photos and such in my library. Maybe the computer or the cloud is prepping them for export but after a coupe tries and a few hours waiting I get no indication anything is happening. And the down (load) arrow is greyed out. I'll call Apple Tech support and get them to walk me through this. Thanks for your help. D

Plug the external drive into a computer and download directly to the external drive from icloud.com

will do. I can see it's hands on. Much appreciated

D