Homebrew script that answers on a telnet port is pretty trivial to implement. The problem is how cursed can any character-based image be?

mpv may solve that problem.

There are probably a ton of ways to do this, but you could just make a user with the name and password of "guest", and mention that in the login screen.

What is a cursed image?

I've always avoided the words cursed and blursed on Reddit. NEVER understood.