Originally, there were no images of the Buddha himself: anything needed to represent him was either a set of his foot prints, or else, later, the stone Stupas which are ubiquitous in Asia. However, after contact with those sexy Greeks, the whole game changed. Just as the persecuted Christians of ancient Rome raised the crucifix as a sign of their avatar – – the shamefully executed criminal raised to invisible hero – – the Greeks transformed the intangibility of “Buddha“ (the self-awakened mind) into their own heroic ideal, albeit with a far, far more nuanced (even deeply sensualized) interior-directed and soft sense of spiritual heroism.
For our purposes, the means of transmission matters less than the fact that the models and iconography of Greek art were integral to the development of an increasingly standardised image of the Buddha. That image would have a long history, moving with the faith into central Asia, China and Japan, and changing as it travelled. Yet, even today, in shrines and sanctuaries scattered across Asia and beyond, it bears traces, faint but real, of the Greek encounter with Buddhism two millennia ago.
This article is an excellent, well thought-out exploration of why Buddhist iconography was derived so strongly from Hellenistic models of statuary.
H/T: Addison Hodges Hart