Change background gnome-

[zevues]

Hi guys,
I'm using Xubuntu 18.04 and I changed the default with:


apt purge light-locker
apt install gnome-screensaver


The problem is that I can't change the default wallpaper of the lock screen.

I tried:
1-way


gsettings set org.gnome.desktop.screensaver picture-uri file://image.jpg
gconftool update

but nothing changed even if the command:

gsettings get org.gnome.desktop.screensaver picture-uri
gives the right value.

2-way
I tried to follow this (https://help.gnome.org/admin/system-admin-guide/stable/desktop-shield.html.en) tutorial and so:


apt install dconf-cli
edited the file: /etc/dconf/profile/gdm
mkdir /etc/dconf/db/gdm.d/
created the file: /etc/dconf/db/gdm.d/01-screensaver
dconf update
reboot the system

but nothing changed.

3-way
As a last resort I tried to link my image as:


ln -s image.jpg /usr/share/xfce4/backdrops/xubuntu-wallpaper.png

because this is the wallpaper that gnome-screensaver uses as default.

Any suggestion?