A very interesting topic about the origin of Christian iconography and art. Where do we have to look for the sources of this art: in Antiquity, in ancient Greece? In Judaism as well. Sinagogue in ancient town Dura Europos in Syria(destroyed in 256 A.D)is a good example of this. Here are almost the only known anthropomorphic depictions in judaic art in Dura Europos sinagogue: scenes from the Old Testament, priests, prophets... If we want to understand the origin of the Christian iconography we have to keep in mind also these unique frescoes.
http://onbehalfofall.org/iconography-in-ancient-house-churches/
