Private scans

Is anyone paying for a private scan so they can announce their pregnancy on christmas day? My hospital scan isn't until January but we want to announce in christmas but of course want to make sure its all viable before we do. When would be the best time for me to book a private scan? Im currently 7 weeks. We want to use the scan photos to put in cards for family so want to the photos to be quite decent of the baby.

Thanks xx