SDDM Theme HotDog is a light and clean theme for the Simple Desktop Display Manager. It is the recommended display manager theme to login to your suckless dynamic window manager. This theme is based on QtQuick2.
The wallpaper was probably taken from a misguided thread on 4chan.org/b/.
Installation should be easy. Simply put the folder named 'hotdog' to your sddm themes folder.
sudo cp -r hotdog /usr/share/sddm/themes
Enjoy and don't fuck things up.-)