I just added some new goodies into the Downloads section; some stock art (layered Photoshop files, actually) I whipped up, featuring some science-fictional planets. 

The files are roughly 1000-1500 x 1000-1500 px, at 72 dpi (so, ideal for web-based use, but not suitable for print). 

And remember: there are some other resources in the Downloads section, so poke around and download away.

Enjoy!