This guide show you how to give you login screen a background taken from your wallpaper of your user with blur effect.
WARNING: It’s on experimental level and can be unstable, so use it at your own risk!
First you need to install proper packages/libs -dev to use for building a new greeter. Open the terminal and copy/paste;
sudo apt install git libgdk-pixbuf2.0-dev libgranite-dev libgtk-3-dev liblightdm-gobject-1-dev libwingpanel-2.0-dev libx11-dev meson valac libmutter-2-dev
A lot of packages will now be install for compiling and building.
This will download the source of the greeter;
cd && cd Downloads git clone https://github.com/elementary/greeter.git
Compiling and Installation
Now to the compiling the source of the greeter and installation of it;
cd greeter meson build --prefix=/usr cd build ninja sudo ninja install
Now logout and see your new greeter.
Tested on: elementary OS 5.1.4