Do you want to display the background image randomly in Beaver Builder Row? You can set only one image as a background image in Beaver Builder row. In this article I am showing how you will upload the multiple photos from row settings form and randomly display the image (every page refresh image will be changed) at front-end.
Adding Fields into Row Setting Form
Editing the row settings form and adding some extra new fields there. Beaver Builder have a filter fl_builder_register_settings_form. So you can edit the default settings form as per your requirement. I added the following PHP snippets in functions.php file of my active theme.