Zero-knowledge seems completely unnecessary. Surely the original image does not have any material content in it that is not made public by publishing a JPEG-compressed version.
Could this be simpler and more efficient without ZK?
Could this be simpler and more efficient without ZK?
The proof must be MUCH smaller than the whole computation or even the inputs (otherwise, just provide the uncompressed image!).
And the proof has to resist forgery.
So going for succinctness and at least computational soundness gets you to zero knowledge 'for free'.
Plus as the dead sibling comment notes: You may want disclosed modifications like a crop or redaction where the committed information remains private but you want to keep the proof.
Imagine a photo with some blacked out rectangles, and a ZK proof that confirms it comes from an attested "real" photo + adding those rectangles, but no other modification.