e17setroot is what you're looking for.
rtfm at http://get-e.org/User_Guide/English/_pages/3.4.html
Ohh.. yeah!! That worked!
Don't know why, but I only tried Esetroot knowing of e17setroot...
Regarding the cpu-usage, I was using the following options:
urxvt -tr -sh 95 -tint white +sb -geometry 100x32, and with this, the monitor fly to 101%!
With urxvt -tr +sb it behaves much better..
Other thing in this great screenshots are the bg!! Where do this guys find those bg images?