static std::string MimeToExt(const std::string &mimeType) {
  if (mimeType == "image/jpeg") {
    return "jpg";
  } else if (mimeType == "image/png") {
    return "png";
  } else if (mimeType == "image/bmp") {
    return "bmp";
  } else if (mimeType == "image/gif") {
    return "gif";
  }

  return "";
}
static std::string MimeToExt(const std::string &mimeType) {
  if (mimeType == "image/jpeg") {
    return "jpg";
  } else if (mimeType == "image/png") {
    return "png";
  } else if (mimeType == "image/bmp") {
    return "bmp";
  } else if (mimeType == "image/gif") {
    return "gif";
  }

  return "";
}