Not sure if there is a plugin controlling the image menu or component but to edit the menus you just treat them like a normal menu. You can change the order add items and create different types of menus, ie ‘external links’.
Sometimes it’s easier to duplicate an exsisting menu item to get the functionality you like. If you are adding a new item you’ll need to create 2 .pngs and put them in the image folder…
Everything should be pretty obvious from there onwards. Good luck!