This morning I discovered a notification from Google+ Auto Awesome. An uploaded photo had been enhanced with a snow effect.
According to the post, Two new kinds of #AutoAwesome: Twinkle and Snow by Erik Murphy-Chutorian, on December 5, 2013 two new Google+ effects were released just in time for the holidays.
Upload a photo of sparkly things like a Christmas tree or chandelier may result in an auto awesome version with twinkling lights.
Upload a photo with snow may result in an auto awesome version with snow falling.