Of the thousands of exoplanets discovered so far, less than a dozen have been found using telescopes. The rest have relied upon other more indirect methods, and are typically hundreds or thousands of light years away, not millions.
Mostly planets transiting their stars are deduced through periodic slight dimming or the wobble of the star that is deduced as a planet’s gravitational pull in orbit.
I think the resolution from something 100K miles away and 100 light years would differ.