[Jean-Luc] Marion defines an icon as the visible form of the divine, as found in statues, paintings, and names. An idol is visible, and what makes it function as an idol is the act of gazing: “the idol thus acts as a mirror, not as a portrait: a mirror that reflects the gaze’s image, or more exactly, the image of its aim and the scope of that aim.” Like a mirror, it reflects back the gazer’s ability to conceive the divine, but it also necessarily limits the unlimited godhead. [Like] the absent Buddha of post-parinirvana India, God is invisible, and so the idol limits the divine to what the gazer can imagine. …Icons, however, represent a different approach. Marion contends that an icon and an idol may be contained in the same object, but they serve different functions; they are “two modes of apprehension of the divine in visibility. Of apprehension, or also, no doubt, of reception.” An idol restrains the gaze, while an icon liberates it and opens the mind to imagination. An idol is created for worship of an external figure, while an icon represents potentialities in the gazer, which the act of gazing, followed by internalization, seeks to actualize.
A Bull of a Man: Images of Masculinity, Sex, and the Body in Indian Buddhism,