Gulp workflow to optimize images

gulfile.js

var os = require("os");
var gulp = require("gulp");
var rename = require("gulp-rename");
var parallel = require("concurrent-transform");
var changed = require("gulp-changed");

var imagemin = require("gulp-imagemin");
var pngquant = require("imagemin-pngquant");
var imageResize = require("gulp-image-resize");

var resizeAndMinImagesTask = function (options) { 
    options["imagemin"] = {
        progressive: true,
        interlaced: true,
        svgoPlugins: [{
            removeViewBox: false //https://github.com/svg/svgo/issues/377
        }], 
        use: [
            pngquant()
        ]        
    };

    var cpus = os.cpus().length;

    return function () {
        return gulp.src("src/images/**/*.{jpg,jpeg,gif,png,svg}")
        .pipe(rename(function (path) {
            path.basename += "-" + options.width;
        }))
        .pipe(changed("dist/images"))
        .pipe(parallel(imageResize({width: options.width}), cpus))
        .pipe(imagemin(options["imagemin"]))
        .pipe(gulp.dest("dist/images"));
    }
};

gulp.task("images-1x", resizeAndMinImagesTask({width: 800}));
gulp.task("images-2x", resizeAndMinImagesTask({width: 1600}));
gulp.task("images", ["images-1x", "images-2x"]);

gulp.task("watch", function () {
    gulp.watch("src/images/**/*.{jpg,jpeg,gif,png,svg}", [
        "images", 
    ]);
});

package.json

{
  "name": "image-optimization-workflow",
  "version": "0.0.1",
  "description": "",
  "main": "gulpfile.js",
  "devDependencies": {
    "concurrent-transform": "^1.0.0",
    "gulp": "^3.9.1",
    "gulp-changed": "^1.3.0",
    "gulp-image-resize": "^0.7.1",
    "gulp-imagemin": "^2.4.0",
    "gulp-rename": "^1.2.2",
    "imagemin-pngquant": "^4.2.0"
  },
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "Esteban Martini",
  "license": "ISC"
}