code: func (s *Store) GetImageManifestJSON(key string) ([]byte, error) {
  	key, err := s.ResolveKey(key)
  	if err != nil {
  		return nil, errwrap.Wrap(errors.New("error resolving image ID"), err)
  	}
  	keyLock, err := lock.SharedKeyLock(s.imageLockDir, key)
  	if err != nil {
  		return nil, errwrap.Wrap(errors.New("error locking image"), err)
  	}
  	defer keyLock.Close()
  
  	imj, err := s.stores[imageManifestType].Read(key)
  	if err != nil {
  		return nil, errwrap.Wrap(errors.New("error retrieving image manifest"), err)
  	}
  	return imj, nil
  }
docs: // GetImageManifestJSON gets the ImageManifest JSON bytes with the
  // specified key.