I will jump in here to help [

] , Your pictures must be a .jpg file with the word back at the end of its name, like, “sunnydayBack.jpg” then all you have to do is put your background pictures into Hal’s Characters folder.
You might want to trim or crop your pictures to a square because most of the Hal Haptek play skins have a square Hal window and without trimming the background will get distorted.
Hope this helps.