Changing login background automatically

If I changed my desktop background picture, that picture would also be set to login screen. Now it's not working. Whatever I change, login background is the same picture (Ubuntu's default picture) How can I make it work?

Solution 1:

This question has been answered multiple times, here is an appropriate link.

On your behalf I have tried all answers in this thread on Ubuntu 16.10 and I have only had success with one. Unfortunately it's the ugly one.

Firstly, make sure the picture you want to use is in .png format, then open your terminal:

cd /usr/share/backgrounds
sudo cp /directory/path/to/my/picture /usr/share/backgrounds
sudo mv warty-final-ubuntu.png warty-final-ubuntu2.png
sudo mv 'my-picture-name.png' warty-final-ubuntu.png

Then log out to see your new login wallpaper.

Solution 2:

Add a cronjob /etc/cron.d/variety-background-cp that copies the current background image every 10 minutes to a location outside of your encrypted home folder:

# hourly copy background image
*/10 * * * * your-sername cp "$(gsettings get org.gnome.desktop.background picture-uri|sed "s~'file://\(.*\)'~\1~")" /usr/share/backgrounds/current-background.png

Backup the ubuntu theme file with

cp /usr/share/gnome-shell/theme/ubuntu.css /var/tmp/

edit the #lockDialogGroup section in your ubuntu.css, for example

#lockDialogGroup {
   background: #2c001e url(file:///usr/share/backgrounds/current-background.png);
   background-repeat: no-repeat;
   background-size: cover;
   background-position: center;
}