Gruntfile.js

module.exports = function(grunt) {
  
  var imagemin = require("imagemin"),    // The imagemin module.
  webp = require("imagemin-webp"),   // imagemin's WebP plugin.
  outputFolder = "./img",            // Output folder
  PNGImages = "./img/*.png",         // PNG images
  JPEGImages = "./img/*.jpg";        // JPEG images

imagemin([PNGImages], outputFolder, {
  plugins: [webp({
      lossless: true // Losslessly encode images
  })]
});

imagemin([JPEGImages], outputFolder, {
  plugins: [webp({
    quality: 85, // Quality setting from 0 to 100
    method: 6
  })]
});


    const mozjpeg = require('imagemin');

  // Project configuration.
  grunt.initConfig({
    pkg: grunt.file.readJSON('package.json'),
    uglify: {
      build: {
        src: 'src/<%= pkg.name %>.js',
        dest: 'build/<%= pkg.name %>.min.js'
      }
    }
  });

  // Load the plugin that provides the "uglify" task.
  grunt.loadNpmTasks('grunt-contrib-uglify');

  // Default task(s).
  grunt.registerTask('default', ['uglify']);

  grunt.initConfig({
    imagemin: {
        dynamic: {
            files: [{
                expand: true,
                cwd: 'img/',
                src: ['**/*.{png,jpg,gif}'],
                dest: 'img/compressed'
            }]
        }
    }
});

grunt.loadNpmTasks('grunt-contrib-imagemin');
grunt.registerTask('default', ['imagemin']);


};