I recommend more than a "stern warning" against the possible dangers of idolatry. Remember what happened to all the Old Testament Israelites when they committed idolatry?
Jetavan, with all respect to you as someone more knowledgeable in these matters, I have to disagree that there could be much positive benefit in the identification of Ganesha with Christ. In the OT, again, all the pagan Gods of the Canaanites and such were possibly linked to the God of Israel from a developmental, anthropological point of view, but that doesn't mean that YHWH didn't take care to clarify things for us throughout time. So many years after the fact, we shouldn't still be blurring the categories and synthesizing various religions when the Church has been established by God. Please forgive me if I have blown things way out of proportion, or entirely misinterpreted your comments.
My final opinion is that the idol of Ganesha, or whatever fertility idol it may be, should be smashed to pieces, lest anyone else find it and venerate it.