My Zinogre evolved into Stygian Zinogre if anyone cares... And yes that is Forest and Hills area 1 as background. I think you can unlock more backgrounds by using the fight option, I also have a Shrine Ruins background after I killed a Khezu but then my Zinogre got btfo by a Green Narga, and I don't want it to die so I just kept it save for now :)