On Safari (macOS) it is as impossible to download this easy-to-download-picture as it is possible to download the impossible-to-download-picture[1] from yesterday.
If you can't get the download to work, but are still interested in something similar, @victorgama put together what appears to be a pretty neat macOS implementation. It runs the algorithm on the desktop and automagically refreshes the wallpaper on startup, etc (unfortunately I don't know swift or have a mac, so this is just based on the readme).
[1] https://news.ycombinator.com/item?id=29358880