How to change lightdm's wallpaper per user?

I changed the display manager from sddm to lightdm. I'm using Kubuntu 22.04, and slick-greeter as lightdm's greeter. I remembered that when I was using xfce4 and changed the wallpaper in the xfce4's settings, lightdm's wallpaper was changed when I selected a different user. I want to set the wallpaper up to be changed per user, as I did then. However, I don't want to install xfce4 just for that purpose. Does anyone know how to set up lightdm to change the wallpaper per user without xfce4?