createManyPNGs.js

const fs = require("fs");
const Jimp = require("jimp");

const rootDir = process.cwd();
const outDir = `${rootDir}/img/`;

function createRandomPNG(name, width = 4, height = 4) {
  return new Jimp(width, height, function (err, image) {
    if (err) throw err;
    for (let px = 0; px < width * height; px += 1) {
      const color = Jimp.rgbaToInt(
        Math.floor(Math.random() * 256),
        Math.floor(Math.random() * 256),
        Math.floor(Math.random() * 256),
        255
      );
      image.setPixelColor(color, px % width, Math.floor(px / width));
    }

    image.write(outDir + `${name}.png`, (err) => {
      if (err) throw err;
    });
  });
}

/**
 * @param count number of images to create
 * @param width width of each image
 * @param height height of each image
 */
function createManyPNGs(count = 2, width = 400, height = 400) {
  // create new folder each start
  if (fs.existsSync(outDir)) {
    fs.rmdirSync(outDir, { recursive: true });
  }
  fs.mkdirSync(outDir);

  for (let i = 0; i < count; i++) {
    createRandomPNG(`${i}`, width, height);
  }
}

createManyPNGs(10, 10000, 10000);

use to create tousend of random .png files