Nintendo owns both the trademark (even if not specifically registered) and the copyright, but these are distinct things.
As I'm not a lawyer I don't want to embarrass myself by opining whether or not Nintendo has any claim over photographs of cosplays or other fan art, especially given quite how close two of the "video game plumber" images seemed to be to what they do own. The other two images, being a lot more fan-art-like, are examples where I think it would be an interesting question rather than incredibly obviously too close to Nintendo, although even there "interesting" means I wouldn't be surprised by an actual lawyer saying either of "this is obviously fine" or "this is obviously trademark infringement regardless of what it was trained on".
Now I'm wondering if there even are any videogame plumbers besides Marion and Luigi…
As I'm not a lawyer I don't want to embarrass myself by opining whether or not Nintendo has any claim over photographs of cosplays or other fan art, especially given quite how close two of the "video game plumber" images seemed to be to what they do own. The other two images, being a lot more fan-art-like, are examples where I think it would be an interesting question rather than incredibly obviously too close to Nintendo, although even there "interesting" means I wouldn't be surprised by an actual lawyer saying either of "this is obviously fine" or "this is obviously trademark infringement regardless of what it was trained on".
Now I'm wondering if there even are any videogame plumbers besides Marion and Luigi…