Thanks for the question about removing the background image and doing it globally. If the background image option in the customizer is not removing it completely, then you will need to go into each page and remove the background for each page. Also, make sure to clear your browser’s cache when you make a change. If the problem persists, please provide us the URL for the site and we can examine it in more depth.
If you have any further questions or comments, please let us know.
Kindest regards,
Arnel C.