First of all, I agree without a doubt that this piece needs to be preserved.  Look at the attention to detail with in this piece!  The tiny pictures within each cross piece.  The reflection in the mirror.  Not to mention the symbolism within the piece.  The major fact that the couple was in a secular setting was a big deal.  Also the presence of Christ represented by the candle.  I read that the dog symbolized fidelity.  My question for you is HOW?  Could you better explain the connection?  Is it because of a dog's loyalty thus connecting it to the faithfulness and loyalty surrounding marriage?  It may seem simple, but I had a bit of a time trying to wrap my brain around it.