By the original, I mean the image that was used to produce the initial hash, which Google (rightly) claimed to be CSAM. Without some proof that an illicit image that has the same hash exists, I wouldn't accept a claim based on hash alone.
Oh definitely you need someone to examine the image that was put in the database to show it's CSAM, if the legal argument depends on that. But that's an entirely different question from whether the image on the device is that image.
