Many of those duplicate images are different colors.
Many of those "duplicate" images are actually different colors of the same observation. The raw data appears as a grayscale image but it was originally shot through a different color filter on Huygens. As mentioned below, many of Huygens' images were lost due to a programming error (Huygen's successfully sent data on both of its transmission channels but Cassini was listening on only one channel).
Our glass is half full.
Gary