Broadcast makes it simple to add images right into your Navigation. You can create a drop-down menu with just images or a combination of menu items and images.
Click on the expand icon to the left of the Header this will open the block options:
In the Header content area, you can add image content blocks. These images will map to your menu items. For example, to add an image to the second menu (Shop) we will choose
Item 2 as the Link position in main menu:
On mobile, a single image will appear full width: