Photo faces

I was looking through the iPhoto Library package and came across some jpgs with 'face0' appended to the photo filename. According to the manual, "iPhoto detect all the faces in your photos, and then uses face-recognition technology to group likely matches together". I browsed through some of the 'faces' and amongst the real faces I found this! The algorithm obviously needs refining further - for one thing it does not worry if there is a hole in the head! (background shows through)