From the NY Times technology review:
With the right apps, your smartphone can get a little merrier and can even help you plan for the holidays.
Among the thousands of holiday apps, Santify stands out for its entertainment. It is one of many photo booth apps that take selfie photos and transform them to look more seasonal. Santify does an amazingly good job of turning your selfie into a Santa-like face. It can also create an animated video that can be shared through services like Twitter.
When you open Santify, it shows your phone’s camera, overlaid with handy guidelines about where to place your face. When you have snapped a suitable photo, the app tries to guess where your eyes and mouth are. For the best final effects you can move these marked positions on the screen to better match your image.
Then, with one click, the app processes your photo to add some Santa smile lines, the costume, glasses and more. It also creates a looping video that has a gentle 3-D effect. You can adjust features like beard or mustache style. The results are impressive.
The free app is on iOS. Its downside is that only a few faces (like Santa and Mrs. Claus) are free. You have to pay $1 for each additional face effect.