module.exports = {
    chainWebpack: config => {
      const imgRule = config.module.rule('images')
        imgRule.use('file-loader')
        .loader('image-webpack-loader')
        .tap(options => {
            const ret = options || {}
            ret.pngquant = {
                quality: '65-90',
                speed: 4
            }
            return ret;
            })
        }
  }