loadImage.js

import 'babelify/polyfill'

function loadImage(url) {
    return new Promise((resolve, reject) => {
        let image = new Image()

        image.onload = function() {
            resolve(image)
        }

        image.onerror = function() {
            let message =
                'Could not load image at ' + url
            reject(new Error(msg))
        }

        image.src = url
    })
}
export default loadImage

//Another file with any name
import loadImage from './load-image'

let addImg = (src) => {
	let imgElement = 
		document.createElement("img")
	imgElement.src = src
	document.body.appendChild(imgElement)
}

Promise.all([
	loadImage('images/example1.jpg'),
	loadImage('images/example2.jpg'),
	loadImage('images/example3.jpg'),
	]).then((images) => {
		images.forEach( img => addImg(img.src));
	}).catch((error) => {
		// handle error
	})