Wallpapers

Gnoblin paints a solid black background behind desktop surfaces. It is not a wallpaper client. The shell you run owns wallpaper surfaces and decides how to display them above Gnoblin's background. Configure its wallpaper client using that project's instructions.

To start a separate wallpaper client with the session, add it to Gnoblin's autostart configuration. This example starts swaybg with a solid color:

gnoblin.configure {
    autostart = {
        wallpaper = {command = {"swaybg", "-c", "#242424"}},
    },
}

Install the command first, and use your shell's configuration if it already manages wallpaper. Run one wallpaper client so separate background surfaces do not cover each other.

Apps that request a wallpaper

The GNOME portal backend can show a confirmation preview when an app asks to set a wallpaper. After approval, it copies the selected image to $XDG_CONFIG_HOME/background and updates org.gnome.desktop.background. Your shell still needs to read those settings and display the image; Gnoblin's black background remains behind its surfaces.