Are telescopes used for detailed pictures within our solar system?

Answer

You say in your last sentence:”…must be sent…”
I would phrase that differently as: “…can be sent”

Within the solar system, we can send unmanned spacecraft anywhere, which is not possible for objects outside our solar system. Taking pictures is only a small part of the task of such a satellite. Take ESA’s Venus Express, for example:

http://sci.esa.int/science-e/www/area/index.cfm?fareaid=64

This website describes all the experiments and the necessary instruments. You will see that for a lot of experiments it is really necessary to go to the place. The same goes for the landers sent to Mars. Soil research, research of the atmosphere, research of a magnetic field… can only be done on site. And while that spacecraft is spinning there, it can also take close-up photos, the sharpness of which will be significantly greater than with photos with telescopes on Earth or in orbit around the Earth. The Earth-Mars distance is still about 55 million km, even in the best case scenario. A satellite in orbit around Mars flies just a few hundred to several thousand kilometers above the surface.

We rely solely on telescopes for objects outside the solar system. But here too you have to see it much broader than “taking pictures”. Most satellites for astronomical research are highly specialized in a certain wavelength range, so that an overall picture of an object can be drawn up as much as possible. In addition to the well-known Hubble, ESA and NASA have launched a series of other unmanned telescopes into orbit. After all, apart from visual light and radio radiation, all other wavelengths are blocked by the atmosphere. Agreed, in the infrared there are still a number of windows that are let through, but all UV and X radiation is (fortunately) blocked. Gamma rays are also blocked, although derivatives of interactions between gamma photons with particles in the atmosphere can penetrate to the Earth’s surface.