I am assuming they hash the RAW file. Since JPEGs contain less information than RAW I don't think it is possible to get from JPEG to RAW to hash value matching the one from the original RAW.
The intent is to prove ownership, not to prevent piracy. You can't produce the 'owner' hash with your reconstructed RAW.
I note they also only display low res until you buy a high quality version. That's what I do too. If someone wants to save/share my low res images its no problem. If they want something magazine or billboard res (ie commercial) they have to come to me.
If the pirate registers their own reconstructed RAW file, then there are two 'identical' pictures on the blockchain, and no way to tell which one is the real one. (It doesn't matter that the RAW files don't hash to the same value, because there's no authority who can tell you which version is the 'real' one).
Hi throwaway049, yes thats right, both your comments spot on. The main goal is to prove ownership to support legal sale of image. and the real target for sales are buyers that need top quality high res images. Someone mentioned another idea for combatting pircay, eg identifying photos on the web that may be copies, and that is an interesting service that would be way down the road if at all.