docs: async def async_fetch_image_data(self, image_name, username, password):
          """
              Fetch image data from the Xeoma web server
  
              Arguments:
                  image_name: the name of the image to fetch (i.e. image01)
                  username: the username to directly access this image
                  password: the password to directly access this image
          """
          params = {}
          cookies = self.get_session_cookie()
          if username is not None and password is not None:
              params['user'] = self.encode_user(username, password)
          else:
              params['user'] = ''
          async with aiohttp.ClientSession(cookies=cookies) as session:
              resp = await session.get(
                  '{}/{}.jpg'.format(self._base_url, image_name),
                  params=params
              )
              if resp.headers['Content-Type'] == 'image/jpeg':
                  data = await resp.read()
              else:
                  data = None
          return data