For my Killing Floor 2 server I made a stupid little PHP script that provides cute cat images for the welcome screen banner. It obtains cat images from The Cat API. Each image is cached for ten minutes before it is replaced with a new one, so that all players (who connect at roughly the same time) see the same image. The source code is available on Github and an in-game screenshot is shown below for demonstration.

Killing Floor 2 lobby screenshot