It would be super cool if desktop and mobile web had the ability to properly focus pictures which I think the result of this ticket would provide. The Wikipedia Android app currently detects faces using a platform library. The API by default returns a focus point centered between the subject's eyes as well as the distance between the eyes. We use a proportion of the eye to eye distance to approximate an offset to the nose. It would be neat if users could actually correct poor focus points identified by whatever solution is used and contribute fixes.

http://docs.opencv.org/master/d7/d8b/tutorial_py_face_detection.html