The link says you own the link, and that’s provable via cryptographic checks. Anyone can verify whether you own the link.
And yeah, you could make an NFT of a different link to that same image, but that doesn’t change whether I own my link. Or if the NFT does a content hash, you could slightly change one pixel and make that link, but I still probably own my link.
You could prove you had a link to a JPEG. Whether that link says you own it is up to interpretation.
Also I could upload that same image to another IPFS node and create a new link to that on the Blockchain.
The link says you own the link, and that’s provable via cryptographic checks. Anyone can verify whether you own the link.
And yeah, you could make an NFT of a different link to that same image, but that doesn’t change whether I own my link. Or if the NFT does a content hash, you could slightly change one pixel and make that link, but I still probably own my link.