Support for CSS Background images

[Maingron]

It might be possible to add support for CSS Background images.
Maybe the programmers CSS could then look something like this:

body {
     background-image:url("/img/background.webp");
     background-image-formats: webp, png, jpg;
}

I'm not sure if it's possible to access the CSS's "background-image-formats" through Javascript and I'm also not sure how reliable this would work, but it's worth a try!