NFTs are complicated, and I know this is simplifying, but think of it like a “star registry”. You are registered in a database as the owner of an NFT. What gives it the veneer of legitimacy is that the people who register you are also the people who made the NFT. So it’s better than other similar scams in that sense, in that it’s not just some random organization.
One thing that will vary is whether or not you also have the rights to the image. As in, do you have exclusive rights to make money off the NFT. Sometimes you do and sometimes you don’t. it depends on the agreement you sign when you buy it.
But yes, anyone can copy and paste a digital image off the web, can download and reproduce it exactly. So you can’t have the only digital copy of an NFT. But you are the only “official” owner, it’s like having a deed.
You might then ask, what’s the point? And I’ll answer, I have no idea. That’s why I have never bought one. It seems like a really expensive pet rock fad to me. But that’s just my opinion.
Here’s an extensive thread on the SDMB about NFTs if you want more discussion:
More likely, someone who buys one will brag to MAGA friends on a right wing web site. Set the image as their avatar. And so on.