I work in the refurb department of an e-waste recycling company. I take pictures of monitors and TVs showing Bliss, and I test printers with it. It has bright spots, dark spots, it's colorful, and has plenty of fine detail, making it a decent test picture. Bonus points for being familiar to most people.
Ironically, I only run Linux at work.
High-res version for your modern desktop:
https://archive.org/details/bliss-600dpi
I would love to see the actual negative and the other shots he took at that location.
Isn't there debate in the community that this photo was actually altered and that he has been lying about it?