wallpaper - manage the system wallpaper.
$ wallpaper [--show-all] [--show-current] [name]
The wallpaper utility can be used to set the system wallpaper and list available wallpapers in the /res/wallpapers/ directory.
-a, --show-all: Show all wallpapers-c, --show-current: Show current wallpaper-r, --set-random: Set random wallpaperSet wallpaper to /res/wallpapers/grid.png:
$ wallpaper grid.png
List available wallpapers:
$ wallpaper -a