<p>Most of them are stock photography images. Some are Getty. I don't remember the other places. It says in one of the pop ups who shot it and where it came from. You can probably go there and license the images for you to use.</p>
<p>There's a fantastic app in the Store called Dynamic Theme that will let you use the Windows Spotlight images from the Lock Screen on your desktop. I use it on multiple machines and it's great.</p>