Custom CSS for Footer

[gospodinwizard]

I wanted to add a background image to the margins of the home page so I used this as a template:

body {
 background-image: url("https://www.website.com/image.png");
}

I would like to do the same for the footer but I can't seem to figure out what to replace "body" with to get it done.  I've tried footer, .footer, .footer-bg.  Any guidance, as always, is deeply appreciated.  Thanks in advance...

[toplakd]

Here is good way to start if there is no previous knowledge:

https://www.w3schools.com/css/default.asp

[gospodinwizard]

6 hours ago, toplakd said:

Here is good way to start if there is no previous knowledge:

https://www.w3schools.com/css/default.asp

Thank you very much for the guidance.