Ok, i'll turn this into a more valid question
... is there a desktop changer you can use in Fluxbox?
All i could find was how to set it one time:
1.5.1 Setting Styles and Backgrounds
Selecting a Style (theme) is done by right-clicking the desktop. Menu -> Fluxbox -> Styles
and also under Menu -> Fluxbox -> User Styles
System styles are kept in /usr/local/share/fluxbox/styles as default. The path must be readable by non-root users to be accessed, or copy them to ~/.fluxbox/styles.
To change the background, a few commands are available. I use fbsetbg. The syntax is:
fbsetbg [ -fFcCtTaA /path/to/wallpaper ] [-l] [-h] [-d] [-p]
-f Set fullscreen wallpaper
-c Set centered wallpaper
-t Set tiles wallpaper
-a Set maximized wallpaper, preserving aspect.
-l Set previous wallpaper
It makes a file ~/.fluxbox/lastwallpaper for use with the -l option.