Enable localhost images in GMail

gistfile1.js

(function () {
  while (img = document.evaluate('//img[contains(@src, \'googleusercontent.com\')]', document, null, XPathResult.FIRST_ORDERED_NODE_TYPE, null).singleNodeValue) {
    var src = img.attributes.src.value;
    src = src.substr(src.indexOf('#') + 1);
    img.attributes.src.value = src;
  }
})();