What was the 8th picture - it looked like a ringed planet with continents?
It is. Itís supposed to be an inhabited terrestrial planet with a ring system. The Celestia Motherlode I linked has tons of add-ons for the program by numerous third party users, which I've installed many of.
Many are based on real astronomical objects, both in our star system and others, and some are based on the hypothetical appearance of known extraterrestrial planets. A good section is devoted to pure sci-fi: Star Wars, Star Trek, Babylon 5, Space 1999, 2001 A Space Odyssey, and others.
The Orion's Arm and Arc Builder series are great for entire systems with beautifully developed planetary systems. Many of my posted screens come from them...plus a little Photoshopping in a few of them.