It's proportional to the aperture diameter and inversely proportional to the wavelength. That's why they needed telescopes that spanned the globe for that image

It's proportional to the aperture diameter and inversely proportional to the wavelength. That's why they needed telescopes that spanned the globe for that image of a black hole. More photons does get you shorter exposure times (and therefore better temporal resolution, fair enough). JWST by the way is able to resolve at this theoretical limit, which is just wild.