What's the difference between a Draft album and a Published one?

A draft is your private work-in-progress — only you can see it, and none of the share links work for guests yet. Publishing flips the switch and makes the album live, so anyone with the guest link or QR code can get in and start finding their photos. You can bounce between the two states whenever you like, which is handy: build the album as a draft, upload everything, check it over, then publish when you're ready. There's a "Mark Draft" / "Publish" button right on the album edit page.