They are doing it on bitcoin now by storing the whole image data in a transaction. Someone minted a full block (4MB) NFT yesterday. Since these transactions are

They are doing it on bitcoin now by storing the whole image data in a transaction. Someone minted a full block (4MB) NFT yesterday. Since these transactions are considered non-standard and won’t be propagated by nodes they have to go directly to the miner out of band. The 4MB paid no transaction fee put payed the miner $18000 privately