When people start thinking a screenshot for a game is fake because it looks bad, I think we're all in trouble.
Well, it's a valid concern. We expect games to be flashy these days. And we don't expect gamemakers to go with poor design choices unless we're talking about, say, Ninjabread Man. And sometimes calling a bad screenshot fake is justified. Remember screenshots saying Bomberman would be in Smash Bros. Brawl? One such screenshot was very blurry, making it look like it was plausible.
For the record, I think it looks fake too. But first, I'll point out some other things. Funky Kong and Dry Bones' faces look stretched, the two Boos and Goombas look way too similar, and that baby Bowser fellow to the right of Luigi is creeping me the heck out. Are those big teeth and gums I'm seeing? What am I looking at there? Glad to see King K. Rool and Kamek (or Magikoopa, whatever), surprised to see Wiggler and Monty Mole though. And Paratroopa looks ridiculous with the wings growing out of his head, although I can see why just to distinguish the two koopas.
Also, I'd expect Donkey Kong to be in that roster somewhere (nevermind that he's in the upper-left corner). I see a grayed-out spot, suggesting that chosen players are grayed out, but that doesn't look like DK's silhouette to me, looks like Bowser's silhouette. Oh, Bowser's below. So yeah, where's DK's silhouette?
...since when were a winged and unwinged creature considered separate characters? Are they really that desperate to fill up spaces?