Do note that scrapers will adapt to this. Its very easy to just add an extra noise filter over the image that obviates any impact this might have.

Congratulations! You just won today's, *I don't have the faintest clue what I just read* prize, and it's only 09:00. Your prize is in the post 😉

They mention this in the about section of the website, but are confident they can continue to adapt the process as well.