This could still be a grey area. Obviously pornography of young children could be identified by most people 99% of the time, the 1% being bizarre situations like mistaking a collection of cherub images for child pornography. But what about when the 'child' looks like a junior or senior teenager and so it's ambiguous as to weather they're of legal age or not? Is someone morally obligated to report potential child pornography in such a situation? A false report, even an accidental one, could cost an innocent person their freedom or a lot of money to preserve their freedom.