The background photo was made by myself on an excursion with SOVON in the early morning just outside of Nijmegen, The Netherlands.
Login window has been copied (and slightly modified) from Mcder3's Helium One KDM4 theme.
But hey, that's what the GPL is for right? Thank you very much for your great work!
I've also uploaded a KDE Splash, 1920x1080 background, and the original full-size photo for your convenience.