Vložte nasledujúce pravidlá css do ~ / .config/gtk-3.0/gtk.css (vytvorte súbor, ak neexistuje).

(Použite svoju vlastnú cestu pre pozadie)

Potom reštartujte phosh pomocou

micro ~/.config/gtk-3.0/gtk.css
sudo service tinydm restart

/*
 * Set a background for the lockscreen.
 */
phosh-lockscreen, .phosh-lockshield {
  background-image: linear-gradient(rgba(0, 0, 0, 0.7), rgba(0, 0, 0, 0.7)),
                    url('file:///home/user/Pictures/background.jpg');
  background-size: cover;
  background-position: center;
}

/*
 * Set a background for the app grid.
 */
phosh-app-grid {
  background-image: linear-gradient(rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.5)),
                    url('file:///home/user/Pictures/background.jpg');
  background-size: cover;
  background-position: center;
}