The principle remains, which makes it possible for anyone to do on any blockchain really. Encoding an image into the message of a transaction (or spanned over

The principle remains, which makes it possible for anyone to do on any blockchain really. Encoding an image into the message of a transaction (or spanned over multiple transactions) should be fairly straightforward even with a simple bitcoin wallet. You should be able to make a CSAM NFT on Ethereum that nobody can expunge, as well.