PostCSS plugin convert background imgs to inline base64 string..
.foo {
background: 'b64--- img/test.png ---';
}
.foo {
background: 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAoAAAAKBAMAAAB/HNKOAAAAGFBMVEXMzMyWlpajo6O3t7fFxcWcnJyxsbG+vr50Rsl6AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAJklEQVQImWNgwADKDAwsAQyuDAzMAgyMbOYMAgyuLApAUhnMRgIANvcCBwsFJwYAAAAASUVORK5CYII=';
}
postcss([ require('postcss-base64') ])
See PostCSS docs for examples for your environment.