rework-plugin-inline

inline() plugin for rework, formerly included in core

.inline(dir)

Inline files from dir directly to CSS. Replace inline(path) to Data URI with base64 encoding of file. It is useful for small images and fonts.

Of course, you can use inline only with node. It is not available in the browser with component.

var css = rework(read(css))
  .use(rework.inline('images/', 'fonts/'))
  .toString()

.logo {
  background: inline(icons/logo.png);
}

yields:

.logo {
  background: url("data:image/png;base64,iVBORw0…");
}