Extract /usr/share/gnome-shell/gnome-shell-theme.gresource
copy in the wallpaper. It seems to need to be compiled in to the gresource file.
edit gnome-shell.theme.gresource.xml to add the local wallpaper
edit gnome-shell.css to set it
compile it back up with glib-compile-resources
Attached is a compiled resource with the wallpaper in it. It's just a hacky test.
Method to "fix":
Extract /usr/share/ gnome-shell/ gnome-shell- theme.gresource theme.gresource .xml to add the local wallpaper resources
copy in the wallpaper. It seems to need to be compiled in to the gresource file.
edit gnome-shell.
edit gnome-shell.css to set it
compile it back up with glib-compile-
Attached is a compiled resource with the wallpaper in it. It's just a hacky test.