I was listening to a recent panel discussion with William Albrecht and David Withun and a caller called in and asked if they could name any father before the 300s that used images in the church. Albrecht pointed to Tertullian, in his work on Modesty. In that work he makes reference to the image of a shepherd on a chalice. Even this reference (which is the best they could muster) falls short.
Tertullian's reference to an image on a chalice is part of a very flowery discusssion, not of his own practices, but of those of a different sect (one that, according to him, tolerated adultery). His words: "to which, perchance, that Shepherd, will play the patron whom you depict upon your (sacramental) chalice" (note the "your").
By "Shepherd," there, Tertullian is referring to the Shepherd in the book called the Shepherd of Hermas, a non-canonical early writing.
Contrasting with that, Tertullian describes himself by saying: "I, however, imbibe the Scriptures of that Shepherd who cannot be broken."
You can break a cup, but you can't break the Scriptures.
(Augustine was mentioned in the talk, but he was against the practice that was budding in his day.)