How to add image in post footer

I am using the Kind-of-Business theme. How do I add a background image to the bottom of my post?? Something like this blogsite: https://www.kevinandamanda.com/whatsnew/

See how she has the ribbon at the bottom of her post? How do you do that with the theme i”m using?? I already have a background image for the top of my post. Now I want one for the bottom of my posts.

Thanks!!

My blog: https://www.homemakerinprogress.com/blog