Not necessarily. Let's say the suing party delivered photos of a harm that were alleged to be done by the defendant. That's first of all purjury (sp?), A crime in itself.

Discovering this can lead to dismissal (with prejudice), but even without the fake photo, there might be a strong case against defendant.

Not necessarily. Let's say the victim delivered photos of a harm that were alleged to be done by the defendant. That's a crime in itself. But based on this item the DA orders investigation and finds evidence of a real crime.

Discovering that the photo was faked can lead to dismissal (with prejudice), but even without the fake photo, there might be a strong case against defendant.

Also, the photo could not even be used as evidence in the actual trial stage. A good defense attorney might manage to convince the judge, that the doctored photo should have been discovered such early in the investigation, but I doubt, that one could manage to make everything else in a proper investigation fruit of the poisoned tree unless police screwed up.