code: AlbumArt getArtwork(int artworkId, SlotReference slot, CdjStatus.TrackType trackType, Client client)
              throws IOException {
  
          // Send the artwork request
          Message response = client.simpleRequest(Message.KnownType.ALBUM_ART_REQ, Message.KnownType.ALBUM_ART,
                  client.buildRMST(Message.MenuIdentifier.DATA, slot.slot, trackType), new NumberField((long)artworkId));
  
          // Create an image from the response bytes
          return new AlbumArt(new DataReference(slot, artworkId), ((BinaryField)response.arguments.get(3)).getValue());
      }
docs: Request the artwork with a particular artwork ID, given a connection to a player that has already been set up.
  
  @param artworkId identifies the album art to retrieve
  @param slot the slot identifier from which the associated track was loaded
  @param trackType the kind of track that owns the artwork
  @param client the dbserver client that is communicating with the appropriate player
  
  @return the track's artwork, or null if none is available
  
  @throws IOException if there is a problem communicating with the player