Simple Theme - Creating banner images on collection pages
From Spiffy Stores Knowledge Base
The Simple Theme allows you to have individual banner images on every collection, product, page, blog, and blog article. The process to add these in is very straightforward, and is unique to this theme. This tutorial will not work in other themes.
Creating your image
All banner images are restricted to be the same height and width as you have set the slideshow on your home page. If you have modified the size of the slideshow on your home page, you will need to ensure that your image sizes match those of your home page for consistent display.
The banner images are all in landscape format. If you use a portrait image, you'll be slowing down you site for an image that will likely look awful.
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