Kickstart - Wallpaper configuration

I am writing a kickstart file for an automated & custom CentOS 7 (Gnome 2) installation. I would like **to set the same desktop wallpaper for all my users** (not only root). I didn't find any good example about setting a desktop wallpaper in a kickstart file ... I think I have to modify the following code : gsettings set org.gnome.desktop.background picture-uri ${URI} But how do I apply this for all users created during the kickstart ?