function preload() {

  img = loadImage('loadImage_0.png');

}

function setup() {

  createCanvas(400,400, WEBGL);

  background(128);

​

  // method 1: draw an image + nofill rect

  // they must be the same size

  image(img, 0, 0);

  noFill();

  rect(0,0,100,100);

​

  // method 2: use WEBGL, texture + rect

  // the rect may be any size, image will warp

  translate(-100,-100)

  texture(img);

  rect(0,0,40,150);

}