This is dependent on what the NFT actually gives access to or is linked to. 90% of NFTs probably are just ownership certificates of JPGs so if that is what you

This is dependent on what the NFT actually gives access to or is linked to. 90% of NFTs probably are just ownership certificates of JPGs so if that is what you want to "view" then the answer probably is "a JPG". Other NFTs though might be some sort of online game char, access tokens to a live feed or just symbols of on-chaining offchain consensus. In those cases the answer isn't that straight forward. But generally I'd remark that an NFT in itself only has utility as long as you have access to its underlying chain, so if you cannot take the interaction with the chain with you its not going to be very useful. OTOH, if your sole purpose is looking at pretty pictures then one will probably best just compile JPGs to a folder. But that doesn't mean that one owns those pictures or that there are NFTs involved.