README.md

example.js

require("./style.css");

style.css

body {
	background: url(image.png);
}

webpack.config.js

var ExtractTextPlugin = require("extract-text-webpack-plugin");
module.exports = {
	module: {
		loaders: [
			{
				test: /\.css$/,
				use: ExtractTextPlugin.extract({
					use: "css-loader"
				})
			},
			{ test: /\.png$/, loader: "file-loader" }
		]
	},
	plugins: [
		new ExtractTextPlugin({
			filename: "style.css",
			allChunks: true
		})
	]
};

js/output.js

/******/ (function(modules) { /* webpackBootstrap */ })

/******/ (function(modules) { // webpackBootstrap
/******/ 	// The module cache
/******/ 	var installedModules = {};
/******/
/******/ 	// The require function
/******/ 	function __webpack_require__(moduleId) {
/******/
/******/ 		// Check if module is in cache
/******/ 		if(installedModules[moduleId]) {
/******/ 			return installedModules[moduleId].exports;
/******/ 		}
/******/ 		// Create a new module (and put it into the cache)
/******/ 		var module = installedModules[moduleId] = {
/******/ 			i: moduleId,
/******/ 			l: false,
/******/ 			exports: {}
/******/ 		};
/******/
/******/ 		// Execute the module function
/******/ 		modules[moduleId].call(module.exports, module, module.exports, __webpack_require__);
/******/
/******/ 		// Flag the module as loaded
/******/ 		module.l = true;
/******/
/******/ 		// Return the exports of the module
/******/ 		return module.exports;
/******/ 	}
/******/
/******/
/******/ 	// expose the modules object (__webpack_modules__)
/******/ 	__webpack_require__.m = modules;
/******/
/******/ 	// expose the module cache
/******/ 	__webpack_require__.c = installedModules;
/******/
/******/ 	// identity function for calling harmony imports with the correct context
/******/ 	__webpack_require__.i = function(value) { return value; };
/******/
/******/ 	// define getter function for harmony exports
/******/ 	__webpack_require__.d = function(exports, name, getter) {
/******/ 		if(!__webpack_require__.o(exports, name)) {
/******/ 			Object.defineProperty(exports, name, {
/******/ 				configurable: false,
/******/ 				enumerable: true,
/******/ 				get: getter
/******/ 			});
/******/ 		}
/******/ 	};
/******/
/******/ 	// getDefaultExport function for compatibility with non-harmony modules
/******/ 	__webpack_require__.n = function(module) {
/******/ 		var getter = module && module.__esModule ?
/******/ 			function getDefault() { return module['default']; } :
/******/ 			function getModuleExports() { return module; };
/******/ 		__webpack_require__.d(getter, 'a', getter);
/******/ 		return getter;
/******/ 	};
/******/
/******/ 	// Object.prototype.hasOwnProperty.call
/******/ 	__webpack_require__.o = function(object, property) { return Object.prototype.hasOwnProperty.call(object, property); };
/******/
/******/ 	// __webpack_public_path__
/******/ 	__webpack_require__.p = "js/";
/******/
/******/ 	// Load entry module and return exports
/******/ 	return __webpack_require__(__webpack_require__.s = 1);
/******/ })
/************************************************************************/

/******/ ([
/* 0 */
/* unknown exports provided */
/* all exports used */
/*!*******************!*\
  !*** ./style.css ***!
  \*******************/
/***/ (function(module, exports) {

// removed by extract-text-webpack-plugin

/***/ }),
/* 1 */
/* unknown exports provided */
/* all exports used */
/*!********************!*\
  !*** ./example.js ***!
  \********************/
/***/ (function(module, exports, __webpack_require__) {

__webpack_require__(/*! ./style.css */ 0);

/***/ })
/******/ ]);

js/style.css

body {
	background: url(js/ce21cbdd9b894e6af794813eb3fdaf60.png);
}

Info

Uncompressed

Hash: a7b9259b38bc83b8ca98
Version: webpack 2.6.0
                               Asset       Size  Chunks             Chunk Names
ce21cbdd9b894e6af794813eb3fdaf60.png  119 bytes          [emitted]  
                           output.js    3.06 kB       0  [emitted]  main
                           style.css   69 bytes       0  [emitted]  main
Entrypoint main = output.js style.css
chunk    {0} output.js, style.css (main) 64 bytes [entry] [rendered]
    > main [1] ./example.js 
    [0] ./style.css 41 bytes {0} [built]
        cjs require ./style.css [1] ./example.js 1:0-22
    [1] ./example.js 23 bytes {0} [built]
Child extract-text-webpack-plugin:
                                   Asset       Size  Chunks             Chunk Names
    ce21cbdd9b894e6af794813eb3fdaf60.png  119 bytes          [emitted]  
    Entrypoint undefined = extract-text-webpack-plugin-output-filename
    chunk    {0} extract-text-webpack-plugin-output-filename 1.81 kB [entry] [rendered]
        > [2] (webpack)/~/css-loader!./style.css 
        [0] (webpack)/~/css-loader/lib/css-base.js 1.51 kB {0} [built]
            cjs require ../../node_modules/css-loader/lib/css-base.js [2] (webpack)/~/css-loader!./style.css 1:27-83
        [1] ./image.png 82 bytes {0} [built]
            cjs require ./image.png [2] (webpack)/~/css-loader!./style.css 6:58-80
        [2] (webpack)/~/css-loader!./style.css 222 bytes {0} [built]

Minimized (uglify-js, no zip)

Hash: a59e06b8e4c98e831cac
Version: webpack 2.6.0
                               Asset       Size  Chunks             Chunk Names
ce21cbdd9b894e6af794813eb3fdaf60.png  119 bytes          [emitted]  
                           output.js  530 bytes       0  [emitted]  main
                           style.css   61 bytes       0  [emitted]  main
Entrypoint main = output.js style.css
chunk    {0} output.js, style.css (main) 64 bytes [entry] [rendered]
    > main [1] ./example.js 
    [0] ./style.css 41 bytes {0} [built]
        cjs require ./style.css [1] ./example.js 1:0-22
    [1] ./example.js 23 bytes {0} [built]
Child extract-text-webpack-plugin:
                                   Asset       Size  Chunks             Chunk Names
    ce21cbdd9b894e6af794813eb3fdaf60.png  119 bytes          [emitted]  
    Entrypoint undefined = extract-text-webpack-plugin-output-filename
    chunk    {0} extract-text-webpack-plugin-output-filename 1.8 kB [entry] [rendered]
        > [2] (webpack)/~/css-loader!./style.css 
        [0] (webpack)/~/css-loader/lib/css-base.js 1.51 kB {0} [built]
            cjs require ../../node_modules/css-loader/lib/css-base.js [2] (webpack)/~/css-loader!./style.css 1:27-83
        [1] ./image.png 82 bytes {0} [built]
            cjs require ./image.png [2] (webpack)/~/css-loader!./style.css 6:50-72
        [2] (webpack)/~/css-loader!./style.css 209 bytes {0} [built]