Dreyfus Madonna has a lack of harmony, the posture of the child is awkward and the figures hardly relate to the background or architecture. Despite this there are details which are the signature of Leonardo -- the Virgin's crooked finger and the smoky shadowing or sfumato around her face. Opponents of the suggestion that this painting was by Leonardo point to parallels between this panel and the works of Lorenzo di Credi. Which artist from Verrocchio's workshop was ultimately responsible is certain to remain the subject of much debate.