grunt-contrib-imagemin

gistfile1.js

'use strict';
// following guidelines from http://mattbailey.io/a-beginners-guide-to-grunt-redux/
module.exports = function(grunt) {

    require('load-grunt-config')(grunt);
    require('time-grunt')(grunt);
    grunt.loadNpmTasks("grunt-contrib-imagemin");
    /*grunt.loadNpmTasks("grunt-concurrent");*/

    grunt.initConfig({
        imagemin: {
            all: {
                files: [{
                    expand: true,
                    cwd: '../public_html/',
                    src: ['images2/**/*.{png,jpg,gif}'],
                    dest: '../imagemintest/'
                }],
                options:{
                    progressive: true
                }
            }
        }
    });
    grunt.registerTask("img", ["imagemin"]);
};