That will be done with a solar gravitational lens - there's a recent-ish NASA paper about it. Basically you send your probe to > 550 AU in the opposite direction of your target exoplanet, point it at the Sun and you will get a warped high-res photo of the planet around the Sun. You can then algorithmically decode it into a regular photo.

I think the transit time is likely decades and the build time is also a long time as well. But in maybe 40-100 years we could have plentiful HD images of 'nearby' exoplanets. If I'm still around when it happens I will be beyond hyped.