//defaultCanvas0

function setup() {

  createCanvas(640, 360);

  var c = document.getElementById("defaultCanvas0");

  var ctx = c.getContext("2d");

  img = new Image();

  img.onload = function() { ctx.drawImage(img, 0, 0); };

  img.src = 'http://processing.org/img/processing-web.png';

}

​

​

function draw() {

  background(0);

  image(img, 0, 0, img.elt.width, img.elt.height);

}