function getPhotoForContributor(key) {
  const localImagePath = path.join(PHOTO_PATH, key) + '.jpg';
  try {
    const stat = fs.statSync(localImagePath);
    if (stat.isFile()) {
      return key;
    }
  } catch (ex) {
    // do nothing
  }
  gutil.log('  ', gutil.colors.red(key), MISSING_AVATAR);
  return 'no-photo';
}
Parses & normalizes a markdown file.

@param {string} key The key identifying the user
@return {string} filename to use