How do I put my icloud photos on my mac(full image file) so I can maake a backup disk?

The easiest way is to sync iCloud Photos to your Mac.

On the Mac:

Open Photos

Navigate to photos > settings > icloud

enable iCloud photos

Your library will now sync to your Mac. You can then export whatever images you wish.

So long as you do not have optimize photos turned on on the Mac, yes.