Using an image as a border around entire site

[SamCDesigns]

Hello,

I would like to use an uploaded image to create a border around the entire site. However, I'm not sure where and how to add the code for it. 

Here's the inspiration for what we're trying to create - https://shopparterre.com/

Here's a link to the image URL - https://cdn.shopify.com/s/files/1/0735/6416/0274/files/Elizabeth_Wilson_Designs_Gingham_Border.png?v...

Here's a store preview - https://w9j6i1g508ra83s0-73564160274.shopifypreview.com/

[miguel_liquify]

You could do it by adding these properties to the body

border: 10px solid transparent;

border-image: url(https://cdn.shopify.com/s/files/1/0735/6416/0274/files/Elizabeth_Wilson_Designs_Gingham_Border.png?v=1681729294) 10 round;