They are not cards, they don't store any meaningful data unless you could make the resource immutable.
They are more like "Digital trading links-to-assets-you-have-no-control-over"?
They are more like "Digital trading links-to-assets-you-have-no-control-over"?
NFTs are promoted with those images, and if that's unimportant, then what's the difference between an NFT and some random coin transaction?
In fact, the file is itself only one if many representation of thr artwork. Reencode the jpeg, you get a different file, but we still think it and the NFT are linked.