how to change lightdm and default wallpaper of WM background using mate desktop

hi guys. now, i wanna tell you to change background of lightdm (if you use it haha) and use mate desktop. its begining, because i think "how to change it? with manualy mode, not GUI.?!" so, its not trhought GUI mode. but, this is use the command. and then i will explain how is it.. lets follow this step.

1. first prepare your wallpaper, what you want to applied for background and put in home dir.

2.open terminal and type command below

$cd /etc/lightdm/
# -your favorite text editor- lightdm-gtk-greeter.conf

3. and fill background input with your background file
background = /path/dir/*.jpg or background = /path/dir/*.png
example: background = /home/es-cendol/bg_lightdm/1.jpg

4. its could change user image too, fill at default-user-image input with your avatar.
default-user-image = /path/dir/*.png
example: default-user-image = /home/es-cendol/dNTE.png

5. save it

6. restarting your lightdm, type command bellow
$sudo service lightdm restart

7. tarraa... bingo..

note : this method i tested at ubuntu mate 16.04. so, why you not try at your mate ?.

one more, its could change window manager wallpaper at your desktop. so, you dont need feh, or etc and you dont need put in rc.local to change wm wallpaper; its, dont need. i've been tested with some Window manager like 2bwm, openbox, and pekwm. maybe its done so on i3wm and other wm.
thanks for visit and practice. fail or not, feedback, and etc leave comment bellow, i hope you can do this method and i hope this method is usefull for you.