Update Slideshow Images

[Bloo-dev]

The current slideshow images vary in quality and appeal a lot. We should look into updating the images (especially the one for the public server) to be more appealing.

It may be worth looking into having artist's renditions of the scenes instead of in-game screenshots, these are marketing images after all and need to appeal to the user, whereas screenshots don't seem like a very exciting thing to look at.