... the script can work also as a wallpaper slideshow (i.e. taking a background image - usually a picture - randomly from a folder or supplied from the command line). The picture image can be stretched to full-screen or re-sized and re-positioned on the wallpaper next to XPlanet renderings.
The script is written in Bash (Bourne-again shell), and requires XPlanet, ImageMagick and optionally POM (PhaseOfTheMoon). It should work on all platforms with bash installed and possibly on Cygwin.