This is something I have to share with you all as I love Advent calenders and this one is TOO CUTE! It's by a Dutch company named IXXI and they have 3 Christmas specials this year. Besides these you can also chose to create your own with a collage of your own pictures, a nice blow up or choose from their wide collection of stock images.
It's a flexible design with little square images that you attach with a little X-shaped system. So you can also grow your IXXI over time.