You can check out the contract for the Big Ape Yacht Club NFTs, for yourself[1]
If you go to Contract and then Read, there's a function you can execute towards the end which gets you the URI for a token. If you grab a token ID[2] and enter it in, you'll get back an IPFS address. Should be more permanent than a random image hosting site, but it's certainly not the same as storing the image on the blockchain.