// Get the image
var image = document.getElementById('douglas'),
// Make a canvas
    canvas = document.createElement('canvas'),
    data;

canvas.height = image.height;
canvas.width = image.width;
// Put image on canvas
canvas.getContext('2d').drawImage(image, 0, 0);
// Get base64 encoded data, and un-convert it
data = canvas.toDataURL();
data = atob(data.slice(data.indexOf(',') + 1));
// data is the binary data