next file loader // see next-images

next.config.js

const isProd = process.env.NODE_ENV === 'production'

module.exports = {
  webpack: (config, options) => {
    const {isServer} = options
    config.module.rules.push({
      test: /\.(svg|png|jpe?g|gif)$/i,
      use: isServer ? ['ignore-loader'] : [
        {
          loader: 'file-loader',
          options: {
            name: isProd ? '[name].[contenthash].[ext]' : '[name].[ext]',
            outputPath: 'static/images/',
            publicPath: '_next/static/images/'
          },
        },
      ],
    })

    return config
  },
}