Replacing background image url with CDN image

Hi there,
please note that this is the support forum for the “Black Studio TinyMCE Widget” plugin. Your question seems related to a feature of the Page Builder plugin, so I’d suggest to post on their support forum.
In my opinion you should be able to achieve what you want by using a custom CSS rule (there’s a box for that in the row options of Page Builder) for setting the background image instead of using the specific setting for selecting it from the media library.