code: def download_pic(self, filename: str, url: str, mtime: datetime,
                       filename_suffix: Optional[str] = None, _attempt: int = 1) -> bool:
          
          urlmatch = re.search('\\.[a-z0-9]*\\?', url)
          file_extension = url[-3:] if urlmatch is None else urlmatch.group(0)[1:-1]
          if filename_suffix is not None:
              filename += '_' + filename_suffix
          filename += '.' + file_extension
          # A post is considered "commited" if the json file exists and is not malformed.
          if self.commit_mode:
              if self._committed and os.path.isfile(filename):
                  self.context.log(filename + ' exists', end=' ', flush=True)
                  return False
          else:
              if os.path.isfile(filename):
                  self.context.log(filename + ' exists', end=' ', flush=True)
                  return False
          self.context.get_and_write_raw(url, filename)
          os.utime(filename, (datetime.now().timestamp(), mtime.timestamp()))
          return True
docs: Downloads and saves picture with given url under given directory with given timestamp.
          Returns true, if file was actually downloaded, i.e. updated.