Desktop Background Photos
Recently when I try to change the desktop photo on my Macbook Pro, the photos from the 'Photos' app are not there. I'm using Big Sur.
MacBook Pro 15″, macOS 11.5
i found the same issue with big sur a while back. this works until apple fixes it. (if they ever do)
you can open your photos app. choose a picture and single click it to highlight it. then click the share button at the top of the photos window and choose Set Desktop Picture.