Css image url relative path background

Set the url of the image if you'd like to use an image. If I use an absolute path both find it fine but this not what I want. Is there a trick I can use with relative paths.
Outdoor Wood Christmas Deer Decorations. The background-image property sets one or more background images for an element. Close look at the file path that references that image.

Can it be a relative path as above or must.

The image is from another folder and I try to. I am trying to use indices and trying to give color to each surface of the tetrahedron.