Gulp Resize Images, Example

gulpfile.js

// https://github.com/gulpjs/gulp
var gulp = require('gulp');

// https://www.npmjs.com/package/gulp-image-resize
var imageResize = require('gulp-image-resize');

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

const SIZES = [384, 512, 768, 1024, 1536, 2048];

function generateImages(size) {
  gulp.src("images/original/*.{jpg,png}")
    .pipe(parallel(
      imageResize({ width : size }),
      os.cpus().length
    ))
    .pipe(gulp.dest("images/" + size + "-wide"));
}

gulp.task("default", function() {
  SIZES.forEach(generateImages);
});

package.json

{
  "name": "resize-images",
  "version": "1.0.0",
  "description": "",
  "main": "gulpfile.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "jim@jimthoburn.com",
  "license": "MIT",
  "devDependencies": {
    "concurrent-transform": "^1.0.0",
    "gulp": "^3.9.1",
    "gulp-image-resize": "^0.12.0"
  }
}