I was so focused on trying to get the perfect Christmas card photo when my son was that age. It was ridiculous. I had the outfit picked out. Then he had a diaper leak. Picture got post-poned. Every year it seemed like something made my perfect idea of the perfect Christmas card photo always so difficult to achieve. Someone didn't save the planned outfit and it was dirty. Our son had an accident. The cat wouldn't join our photo.
On our fourth Christmas, after my son was born, the unthinkable happened. We all got terribly sick at the end of November when we usually did the photo, so it got post-poned until the first weekend in December. That turned out to be a blessing in disguise. Laundry had piled up when we were all sick, so the outfits I had planned for us to wear for the card ended up in the dirty laundry instead. I had wanted us to only wear Christmas colors for the photo. Instead, we wore what was available from our closet. I got more compliments on that Christmas card than any of my prior attempts at having the perfect card. It looked natural. It wasn't planned perfection.
After that year, it has been choose your favorite clothes to wear for the photo and let's just have fun taking a photo. We usually take our main photo for our Christmas card gathered around the Christmas tree. We also always include a photo of our Nativity Scene, with a scriptural quote. My favorite scripture to include is Isaiah 9:6. Then, we include two or three of our favorite snapshots from that year.
We live in Japan now, and in addition to sending Christmas cards, my family sends out New Year's cards as well. We usually make a collage of about 7-9 photos on the card with one of the whole family as the central focus. The photos highlight our year, and we include a brief description of our wonderful (and sometimes trying) year. You could do the collage thing for a Christmas card as well.
My advice is to make it natural. It is so much easier, and your friends and family will probably love seeing what really happened versus the planned perfect image. The around the Christmas tree theme and Nativity Scene and scripture make it like a tradition, yet the snapshots make it unique to each year. I really like how our past few years have turned out. It's fun to see how different our tree looks every year too. Good luck and remember that sharing our love with others is the greatest gift. It doesn't really matter if that card is planned perfection. It will be perfect if you are yourselves.