Why file metadata will not save you
Camera EXIF and compression traces are easy to strip, so a fair quiz removes them before you ever look.
A real photo often carries the camera, the lens, and the time. A generated image often does not. That difference is useless the moment someone re-encodes the file, which is a one-line image operation. It is also unfair in a quiz: if the real items still have EXIF and the synthetic ones do not, you can sort them without looking.
SpotAIQuiz re-encodes quiz media to the same format, size class, and quality, and drops metadata, so the file properties are not the puzzle. The picture is. That is also why a “detector” that only reads headers will not help you on the open web, where everyone who cares has already exported a clean JPEG.
What survives export is the content: geometry, text, light, motion, breath. Those are the guides in this section. Credentials such as C2PA are a separate channel, and only when the signature is still attached and the signer is one you trust.
If you are reviewing new quiz items, check the picture and the explanation. Do not check the file info and call it done.