There are two shortcodes available for creating the Mega Menu in Shopi. One is the [full_width_mega_menu] and another one is [heading_menu_list]

<img src="img_1.jpg" alt="left buttom image" />
<img src="img_2.jpg" alt="right buttom image" />
<img src="img_3.jpg" alt="right top image" />

[full_width_mega_menu]
    <strong>Category Pages</strong>
    <ul>
 	<li><a href="#">Category Full Width</a></li>
 	<li><a href="#">Category Left Sidebar</a></li>
 	<li><a href="#">Category Right Sidebar</a></li>
    </ul>
[/full_width_mega_menu]

[full_width_mega_menu]
    <strong>Product Pages</strong>
    <ul>
 	<li><a href="#">Category Full Width</a></li>
 	<li><a href="#">Category Left Sidebar</a></li>
 	<li><a href="#">Category Right Sidebar</a></li>
    </ul>
[/full_width_mega_menu]

[full_width_mega_menu]
    <strong>Inner Pages</strong>
    <ul>
 	<li><a href="#">Category Full Width</a></li>
 	<li><a href="#">Category Left Sidebar</a></li>
 	<li><a href="#">Category Right Sidebar</a></li>
    </ul>
[/full_width_mega_menu]

[full_width_mega_menu]
   <strong>Other Pages</strong>
   <ul>
 	<li><a href="#">Category Full Width</a></li>
 	<li><a href="#">Category Left Sidebar</a></li>
 	<li><a href="#">Category Right Sidebar</a></li>
   </ul>
[/full_width_mega_menu]