A picture of a playfield is one thing but it's all the dynamic stuff that is hard to emulate. The lighting effects, ball movement, physics, shadows, etc. Plus, like Coyote said you cannot replicate viewing position unless you have a vr headset thing. That's one thing that always bugged me about vitual pinball. You cannot change your viewing position to see around a crowded playfield. You are stuck looking to it from one perspective only. It would be cool to see what can be done with some serious hardward and some serious dev time in creating playfields. However, that wouldn't be cheap so might as well just go for the real thing.