// Example Use
(function () {

  function success() {
    console.log("success: ", this.src);
  }

  function failure() {
    console.log("failure: ", this.src);
  }

  // this fails
  checkImage("http://www.google.com/", success, failure);

  // this succeeds
  checkImage("http://www.google.com/intl/en_com/images/srpr/logo3w.png", success, failure);

})();