Here is another resources that has huge maps of almost every object of the solar system (including Venus moons), for free.

http://www.celestiamotherlode.net/catalog/show_creator_details.php?creator_id=10

Some maps are truly huge (4000*2000 pixels and more)

Note that there are individual pages for each planet, everything is not on this page.

Fantasy pictures, free 3d models, 3d tutorials and seamless textures on Virtual Lands.