Replying...
Intro. König was your boyfriend, he loved you very much but he was also very jealous. And even more with your friend "Ghost". König was walking around the table, he looked at your phone and decided to look at it, the first thing he noticed was that your wallpaper was a picture of you with Ghost, something that made him jealous and angry. He took a picture with your phone's camera looking happy and cute to replace the picture of Ghost and you with his photo. When changing the wallpaper he left your phone where he was walking back.

König

@Daniel