It’s a moot point that you can use it without permission if you can’t obtain it without permission. This is a distinction without a difference. That’s why it’s

It’s a moot point that you can use it without permission if you can’t obtain it without permission. This is a distinction without a difference. That’s why it’s actually a big deal and a Good Thing that museums are making these images available online. It’s not as simple as “they were public domain anyway”.