This video linked by another commenter explains it quite well: https://www.youtube.com/watch?v=NQFqDKRAROI https://www.youtube.com/watch?v=NQFqDKRAROI Basicall

This video linked by another commenter explains it quite well: https://www.youtube.com/watch?v=NQFqDKRAROI https://www.youtube.com/watch?v=NQFqDKRAROI Basically, it's possible to generate an image of an exoplanet, but "retargeting" the telescope(s) to observe another object is not feasible. So you'd better make sure the target that the mission will focus upon is actually worth the attention it gets - but there are other planned telescopes that will be capable of generating data that will allow selecting potential candidates.