Here's how a screenshot normally gets from a publisher to a website like this. They're either hosted on a press site or sent via email. Sometimes, if a company is crazy/lazy, they'll only send the versions that print magazines can use, meaning we've got a little resizing to do to get it to a size that won't destroy our bandwidth.
Even at their worst, though, those files are only a few thousand pixels wide. They are nothing like this monstrosity from Sega and The Creative Assembly, for the upcoming Total War: Rome II.
The screenshot you see above is part of it, shrunk to regular internet eyeball size. In its native form, it's 30000 x 9785. Total size? 184mb, which, like Bane with Batman, nearly broke my Photoshop's spine.
Below is a 1:1 scale excerpt. The tiny men on the rock in the top image? It's them.
Sure, it's a silly little marketing stunt, since you'll never actually play the game at a scale like that, but who cares. It's a great way to kill five minutes scrolling for barbarians.
World’s Biggest Total War Screenshot Gets Bigger [Total War]