What is she doing?

I took this picture of Avery last week. When I saw the instant results on my camera screen, I thought we had a winner for her invitation picture that I was trying so diligently to capture. After uploading them, however, I enlarged this one and instantly was drawn to her smile. What in God's name did she do? It looks fake... like I photoshopped a smile onto her face somehow. I still haven't figured out what she did, but man, this smile is C-R-E-E-P-Y.