Changing Windows 10's boot background

Apparently there is a way to change the black boot screen background to something else. I don't know how you do it since I had just found this on a windows 10 transformation video. I remember asking the person about how you're able to do it. They said that they would show me but never did. Also, I doubt that changing the background from the boot screen since that was from an earlier build of windows 10 (Not below creators update though)