What is the figure of a dragon that is prohibited? One descriptor is scales between the joints, and that is determined to be the halakhah. Also, the story how Rabbi Elazar ben HaKappar found a ring on the road with the depiction of a dragon and he insisted that an adult non-Jew nullify the idolatrous status of it -- with 3 laws being learned from his behavior. Plus, the fact that the change of status of any item when it is saved from wild animals or a destructive river, or so on -- so why did he need a non-Jew to change the status, when that ring was just found on the road? It depends on the despair of the original owner, but that assumes that the finder is Jewish and not going to sell it. Also, the prohibition against depicting the celestial bodies - but Rabban Gamliel had images of the moon to help assess witnesses who come to testify about the new moon - but how could he have those images?! What about a menorah? There are concerns about replication. Likewise, the faces that are part of God's heavenly throne - how could those images be replicated? The Gemara distinguishes between worshipping (obviously prohibited) vs. depicting, which seems to have been done, and therefore flies in the face of the prohibition.