CentOS - Oct 2014 - setting background on the command line

I have centos 7

I am using:
gsettings set org.gnome.desktop.background picture-uri
 file:///usr/share/backgrounds/gnome/Wood.jpg

to set the background from the command line...

dconf-editor shows the command worked.

But the picture is not updated???

How do I get the desktop to re-draw?

Thanks,


Jerry