Interesting challenge. I found some clues already incl a link to register. No private key though.
What do you mean by "... the data you got so far"? I am not sure what should be included in this SHA256 hash.
Edit: "the data" could mean everything incl. your postings, the website and so on. If we are only talking about the image it could be everything incl. metadata, size, visible and hidden numbers, fields, pixels etc. in endless possibilities of combinations of these all. Makes no sense this way.
Yeah, this make no sense, if we don't know even what kind of access we're looking for, a long PK or just a mnemonic, also this person gotta try to prove that the prize is legit in a different way, otherwise i don't think the people take this serious because is a considerable amount of money.