var img = new Image();

var imageBitmap;

var doneLoading = false;

let canvas = document.createElement('canvas');

canvas.width = 640;

canvas.height = 480;

let canvas2 = document.createElement('canvas');

canvas2.width = 640;

canvas2.height = 480;

​

var ctx = canvas.getContext('2d');

var ctx2 = canvas2.getContext('2d');

​

img.addEventListener('load', function() {

  Promise.all([

    createImageBitmap(img)

  ]).then(function(images) {

  imageBitmap = images[0];

  doneLoading = true;

}, false);

});

​

img.src = 'https://1.bp.blogspot.com/-52MtzD0GfX0/WvP52CL1WjI/AAAAAAAAOVw/_OpK4JHeWK01d-7IiZ6vzojYGhXqLRXrACLcBGAs/s1600/EMxediL.jpg';