How to prevent loading images in karma runner

How to configure karma to stop loading images while testing? i was trying to use solution from here in my karma.config.js :

var webpack = require('webpack');

module.exports = function (config) {
   config.set({
      browsers: [ 'Chrome' ],
      singleRun: true,
      frameworks: [ 'mocha' ],
      files: [
         'tests.webpack.js',
         {pattern: './assets/img/signup.png', watched: false, included: false, served: true},
      ],
      proxies: {
         '/assets/img/signup.png': '/assets/img/signup.png'
      },
      preprocessors: {
         'tests.webpack.js': [ 'webpack', 'sourcemap' ]
      },
      reporters: ['mocha'],
      mochaReporter: {},
      webpack: {
         devtool: 'inline-source-map',
         module: {
            loaders: [
               {
                  test: /\.js$/,
                  exclude: /node_modules/,
                  loader: 'babel-loader',
                  query: {
                     cacheDirectory: true,
                     plugins: ['transform-decorators-legacy' ],
                     presets: ['airbnb', 'es2015', 'stage-1', 'react']
                  }
               }
            ]
         },
         externals: {
            'cheerio': 'window',
            'react/addons': true,
            'react/lib/ExecutionEnvironment': true,
            'react/lib/ReactContext': true
         }
      },
      webpackServer: {
         noInfo: true //please don't spam the console when running in karma!
      }
   });
};

but this doesn't work for me. I still get error:

[web-server]: 404: /front-end2/assets/img/signup.png

Maybe there are any other solution to prevent loading images ? the biggest problem is not warning message but errors which ocures when karma try to get image from my local server

Solution

The proxies configuration does not look right. Try something like this:

...
proxies: {
    '/front-end2/assets/img/': '/base/assets/img/'
},
...

A brief explanation:

/front-end2/assets/img/ relates to the requests that are being made;
/assets/img/ relates the the pattern in the files configuration; and
/base/ is the path from which Karma serves the files.