"Nor is it strange that those of the Gentiles who, of old, were benefited by our Saviour, should have done such things, since we have learned also that the likenesses of his apostles Paul and Peter, and of Christ himself, are preserved in paintings, the ancients being accustomed, as it is likely, according to a habit of the Gentiles, to pay this kind of honor indiscriminately to those regarded by them as deliverers." - Eusebius, Ecclesiastical History, 7, 18, 4
However, in a footnote for this passage (Schaff's Post-Nicene Fathers), it says:
"Eusebius himself, as we learn from his letter to the Empress Constantia Augusta, did not approve of the use of images or representations of Christ, on the ground that it tended to idolatry. In consequence of this disapproval he fell into great disrepute in the later image-worshiping Church, his epistle being cited by the iconoclasts at the second Council of Nicæa, in 787, and his orthodoxy being in consequence fiercely attacked by the defenders of image-worship, who dominated the council, and won the day."
A search on Google only brought the letter up on a subscription (Journal) site, but this position being held by Eusebius is mentioned in several other places.