Pokemon Snap should work on PJ64, but it still isn't flawless, if it doesn't show any graphics, your rom may be bad. Try checking it with GoodN64 at www.smiff.clara.net .
It does worl with PJ64, but have you ever played it ? You can't phinish the levels, because you can't take any photos, which makes the game useless, cos making photos is what the game is about.
And that is exactly what the FAQ says. They don't have any solution to it, too.
You can´t take photos ONLY in the first level, you use a cheat to unlock all levels and that´s it, you can play the rest of the levels without problem.