1. A system for facial liveness detection in image biometrics, the system comprising: a biometric feature detector to detecting a set of potential authentication faces in an image sequence captured during an authentication attempt by a user; a liveness indication controller to: for each face in the set of potential authentication faces: use an emitter of the system to emit light towards the face; use a sensor of the system to measure an interaction of the light with the face; and invoke a synchronicity detector to: apply a set of liveness model tests to the face, each test in the set of liveness tests including an assay that differs between a live face and a face simulated on a pictorial representation of a face, the assay operating independently of body arrangement instructions given to the user; and compare the interaction of the light with the face with a model of a live face, wherein in at least one test in the set of liveness models tests, the interaction of the light with the face provides a distance measurement between the face and the emitter, wherein the model of the live face includes an acceptable size range of a live face, and wherein to compare the interaction with the model includes the synchronicity detector to scale a visual light spectrum representation of the face acquired from the image sequence using the distance measurement to determine whether the face is within the acceptable size range of a live face; and add the face to a set of authentication faces when the result of the set of liveness model tests meets a threshold; and an authentication controller to apply facial authentication to faces in the set of authentication faces.