Is it correct to say that
an NFT (kept say on the Ethereum blockchain) for an artwork file (say a .jpg or an animated .gif) contains only a single resource locator for where that file is kept (in addition to its other contents), and
typically the locator will be either a) a URL or b) a hash that the owner of a website (or FTP site) has associated (in his own database) with a page or file that he keeps on his webserver (or FTP server)?
If the answer is "Yes", then if the website (or FTP site) disappears the NFT will no longer point to the artwork, right?
If the answer is "No", then what am I missing?