So when I give a build from my eclipse to AEM with a package that contains the theme.css, which was initially created by the theme editor, I dont see the background image in the theme editor even though theme.css has a reference to that background image.
THEME.CSS in crx

THEME EDITOR

Now if I make any changes in my theme editor, it refreshes the theme.css and erases the references and and whatever that were not present in theme.editor like some padding stuff etc.