Source: H. Graetz, History of the Jews, volume II (Philadelphia: Jewish Publication Society of America, 1893) 179.
Graetz states the following about Strabo, a Greek geographer from the first century B.C.E. to the first century C.E., and a proponent of Roman imperialism.
"Although he mentions the Judeans as having originated from Egypt, he does not repeat the legend that their expulsion was occasioned by some fault of their own. Far otherwise he explains the Exodus, affirming that the Egyptian mode of life, with its unworthy idolatry, had driven Moses and his followers from the shores of the Nile. He writes in praise of the Mosaic teaching relative to the unity of God, as opposed to the Egyptian plurality of deities, and of the spiritual, imageless worship of the Judeans in contrast to the animal worship of the Egyptians, and to the investing of the divinity with a human form among the Greeks. 'How can any sensible man,' he exclaims, 'dare make an image of the Heavenly King?'"
I thought I read in the HarperCollins Study Bible's section on the Wisdom of Solomon (written by David Winston) that the Romans looked down on the Egyptian form of idolatry, which tended to focus on animals. I can't find the passage, however, so don't take that as Gospel-truth (unless you know it to be true).
What's interesting is that there were elements of Greco-Roman religion that had a high view of the divine. In the sixth-fifth centuries B.C.E., Xenophanes expressed abhorrence at anthropomorphic depictions of the gods. His view contributed to the allegorical interpretation of Homer, since many thinkers refused to believe that the gods were as human-like as Homer depicted them.
And Winston points out that "Nature worshipers are overly impressed by what they see, whereas the ultimate reality is invisible," according to Plato's Sophist 246A-B. A Platonic view isn't exactly consistent with idolatry (not that I know what Plato believed about it).
I remember reading in John MacArthur's Vanishing Conscience that the Romans once had a belief in one God. I'm not sure if this is true or not, but I find it interesting that Greco-Roman culture had some sense that God is supreme, meaning that images cannot do him justice. Was this a result of God's revelation to all men--through nature, reason, and other means?