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…
I don't see why we need to give Nintendo the exclusive right control the use of Mario for the next 65 years. That duration of control is absolutely not necessary for society to function.
Society would function just fine of the copyright on mario had expired two decades ago.