Even if this particular approach likely provides medium to low assurance, which approach is more trustworthy:
Suppose I take a set of photos that I own, and crop all of them after I magnified by 25%. How reasonable is it to assume I "own" the picture if I share some or all of that cropping?
Is it more or less reasonable to prove ownership by sharing a higher quality image, can that prove ownership if I share a portion of that?
Both of these techniques are used in-practice by various digital media companies. I would assume the degree of cropping / de-resoultion has usability and security tradeoffs and would love to hear about the optimal approach.
Secondarily, I'm thinking this can be used as a UX metaphor in a ZKP/Zero knowledge proof system. If this is actually a viable security scheme, I will hide the technical details (bitcoin) from the user.