PostCSS Resolve Url 
PostCSS plugin which resolve relative url problems in css-loader.
#a.scss
.foo {
background-image: url('./a.png')
}
#b.scss
@import './a.scss';
Output
#b.scss
.foo {
background-image: url('./a.png')
// context is a.scss abdolute path
}
Usage
postcss.plugin('postcss-resolve-url');
See PostCSS docs for examples for your environment.