The built-in function FindFaces
seems to miss faces a lot, for example
i = Import@"https://celebritiesindisgrace.files.wordpress.com/2014/03/2014-oscar-twitter-pic-600x308.jpg";
HighlightImage[i, {"Boundary", Green, Rectangle @@@ FindFaces[#] &}]
Are there other mma implementations of face detection to use?