How do I add a full-width banner image to my collection page?
The Testament, Vantage, Fashionopolism, and Icon themes (if purchased after March 20th, 2016) all have a new shortcode function which makes it possible to show a full-width image at the top of your collection pages without sacrificing the collection description or collection image.
As an example take a look at the wide image on this screenshot of a page.
Adding a Collection Banner Image
To show these on your pages follow these simple steps.
Open the collection page within your Shopify admin that you want to add the full-width banner image to. Scroll to the bottom of the page and click on the "Edit Website SEO" link as pictured below. The last section here is named: URL and handle The handle is the piece that appears right after /collections/ in this instance, the handle is: best-selling
Create a 1920px wide (minimum size) image and name it identically to the handle of your collection above in Step #1. make sure it is identical, all lowercase and saved as a .jpg file. For this example, our image would be called best-selling.jpg. If your collection handle is called dresses then you would be saving the image as dresses.jpg.
When ready click on Shopify Admin > Setting > Files and upload your image. You need to do nothing more here.
Go back to the collection and inside the collection description and add [banner] and click save.
This will now add that image to the top of this collection page, you may add any additional content to the collection description, this will appear a little further down the page. Click Save and repeat for your other collections.