Data from all science instruments on all of NASA's and ESA's space missions, not just cameras, is archived in the Planetary Data System and Planetary Science Archive, and almost all of that data is available online.
The Mars Exploration Rover Opportunity has been studying a lot of meteorites. That made me wonder, why study meteorites on Mars when we can study them in hand on Earth? How are Mars meteorites interesting?
In the beginning was SETI@home, the first large-scale volunteer computing project, launched in 1999 with seed money from The Planetary Society. Within months the project had millions of volunteers around the world joining to form the most powerful computer network ever assembled.