The first simulated images were actually computed decades ago, but I think Interstellar had the most detailed simulation by a high margin

https://www.cnrs.fr/en/press/first-ever-image-black-hole-cnrs-researcher-had-simulated-it-early-1979

Interstellar spent 100 hours of mainframe compute time per frame to simulate a black hole

https://www.indiewire.com/features/general/black-hole-photo-christopher-nolan-insterstellar-predicted-look-1202057414/