Go to your Online store > Themes > Edit code > open base.css file, add this code at the bottom, and save the file
#footer { background-img: url('https://community.shopify.com/c/image/serverpage/image-id/379358i382A72C804F79777/image-size/large?v=v2&px=999'); }
Recommend you upload this image to your store admin > Contents > Files copy link and replace it with the current link in my code
