Hello @wbc,
Thanks for writing in!
Please understand how background images work first. You can check out this demo link:
At the moment, we do not have a responsive background image option. When you use the background option of the Section, Row, or Column, you only have one image that you can insert.
If you want to have a different background image for desktop and a different image on mobile, you can use two DIV elements inside a section or Column and then position it as “Absolute”. You can hide the first DIV on mobile and then display the other one on desktop. It could be something like this:
Hope this makes sense.