candycode

// Simulate a call to Dropbox or other service that can
// return an image as an ArrayBuffer.
var xhr = new XMLHttpRequest();

// Use JSFiddle logo as a sample image to avoid complicating
// this example with cross-domain issues.
xhr.open( "GET", "http://fiddle.jshell.net/img/logo.png", true );

// Ask for the result as an ArrayBuffer.
xhr.responseType = "arraybuffer";