Sometimes, you might found our megamenu has background image as example below
Everything can be done easily with WPBakery Page Builder
Once you’ve created a new Mega Menu. You can back to megamenu content editor by clicking Settings on your menus
Select content tab
Now select the Row container and click on Edit button
The Row Settings panel will showed up, now switch to Design Option tab
Scroll down until you see the Background setting, click on [+] button to add more background image
Once your background image has been set. Save changes for your work and check the result.