Adding wallpapers in gnome shell in Debian

Hi.
I'm trying add wallpapers in /usr/share/backgrounds/gnome . And I already put the image file jpg in local specified before and added configuration in /usr/share/gnome-background-properties/gnome-backgrounds.xml .

<wallpaper deleted="false">

                <name>NNNN</name>
                <name xml:lang="pt">nnnn</name>
                <filename>/usr/share/backgrounds/gnome/nnnn.jpg</filename>
                <options>zoom</options>
    <pcolor>#ffffff</pcolor>
    <scolor>#000000</scolor>
        </wallpapper>

But they won't displayed in Settings - Background.
What I should to do to new image to be displayed?

Nobody to try help me.In tha made wrong?