"If the frescoes can survive mortar fire, which must be far more developed than in previous wars, there still remains another risk which lurks around the corner. Should the regime fall, as seems quite probable, the fate of the frescoes might very well lie in the hands of the Salafists."Which means something like this could happen. Related story and commentary here.
Background on Dura Europos and its synagogue frescoes is here with many links.