I installed mate desktop environment on Ubuntu18.04 within a Singularity container by using
apt install -y ubuntu-mate-core
I copied my customized background image to /usr/share/backgrounds and added an entry to the xml file, so that my customized image is in the background list.
However, after login, the default wallpaper is always 'No Desktop background'.
I want to set the default wallpaper to my customized one, is there a configuration file somewhere I can edit to make the customized image always the background wallpaper?
Also, every time after login there's a bluetooth exception
org.freedesktop.DBus.ServiceUnknown: The name org.blueman.Mechanism was not provided by any .service files
I don't require bluetooth at all, how can I disable this?