While the Greeks made offerings to their gods, during the Classical period, the gods are often shown performing libations or holding ritual objects, most often a phiale. The question is whether the deities are performing a ritual or are being shown as the recipients.
Beazley, John D. 1963. Attic Red-figure Vase-painters, Vols. 1 and 2, 2nd ed. p. 649, no. 40, Oxford: Clarendon Press.
von Bothmer, Dietrich. 1984. "A Greek and Roman Treasury." The Metropolitan Museum of Art Bulletin, 42(1): p. 8.
Kossatz-Deissmann, Anneliese, Brigitte Servais-Soyez, Fulvio Canciani, Giovannangelo Camporeale, Hans Peter Isler, Ingrid Krauskopf, Odette Touchefeu-Meynier, Marcel Le Glay, and Dr. Jean-Charles Balty. 1988. Lexicon Iconographicum Mythologiae Classicae, Vol. 4: Eros-Herakles. Hera, no. 143, Zürich: Artemis Verlag Zurich und Munchen.