Share your experience!
You can get those pictures from your other Xperias and transfer them to your Xperia Z1 or download those wallpapers from the XDA forum
Those wallpapers are system files.
Using any file browser > system > etc > customization > content > com > sonyericsson > wallpaper picker > walpapers ..
@VasMes wrote:
But we need ROOT to copy wallpapers into Z1!?
No, you won't need root to copy them. (You can clearly read them without rooting, right?
You jsut can't change them.)
You can use your favourite filebrowser and just copy/share them, for example Ghost Commander. (Available for free in Play or F-Droid).
https://play.google.com/store/apps/details?id=com.rhmsoft.fm
I've just copied all of them with it, so it works without a root 
You can't copy to that location because those are system files. You will have to root your phone in order to do that.