UPDATE: looks like they removed that shortcode or maybe they never had it, just browse the pages you will see a page called shop. Add your image/banner to that page. I just tested this and it works fine, just make sure when you use the add media button that you also insert into page.
Or if you want it somewhere specific just use css and add the class in your header.php where ever you want it to show up…
<div class=”banner”></div>
Make your css classes for each page you want it to show up for called
.woocommerce .banner{background: url(yoururl/Shop.jpg) no-repeat scroll center top transparent;}
.blog .banner{background: url(yoururl/Blog.jpg) no-repeat scroll center top transparent;}
.home .banner{background: url(yoururl/Home.jpg) no-repeat scroll center top transparent;}
Now for each page check in firebug or chrometools but each page should have something unique in the body class most of the time the home page will have home in the body class so you can see how my example above would work. Hope this helps.