DJ-MegaMenu comes with a built-in functionality that allows displaying a background image for a submenu of each menu item.
To do that you need to follow few easy steps:
I assume that you already have the DJ-MegaMenu module installed and published on your site. If not, please check the documentation .
Go to Menus -> [menu name] and edit the menu item for which you want to add a background image to a submenu.
In the menu items settings, go to the DJ-MegaMenu Options tab.
Here you will find all settings related to the DJ-MegaMenu module.
Scroll down to the Submenu Background section.
Click on the Select button next to the Background Image option and select the image you wish to display for a submenu (1).
Below you will find two additional options for controlling the horizontal (2) and vertical position (3) of the image.
Save the settings and you should see the background image applied to the submenu:
Repeat the steps for other menu items where you want to add a background image to a submenu.