Astronomers can currently detect planets outside our solar system through indirect methods like observing the changes in light from the distant stars when its planet passes across it. They have been doing this for more than 15 years, but unfortunately have not documented clear pictures of any exoplanets.
Firstly, even the closest star is several light years away. So when the astronomers observe these stars from an astronomical distance, their orbiting planets appear very close to the star. That defect disables the telescope from detecting them.