It’s typically an IPFS hash of an image that is stored on the blockchain, rather than a mutable URL. Some generative artworks will even store all of their code

It’s typically an IPFS hash of an image that is stored on the blockchain, rather than a mutable URL. Some generative artworks will even store all of their code on-chain. Ultimately, the chain is meant to be a ledger of transactions (like a decentralized Christie’s auction house maintaining provenance), not a storage layer.