Using elementary OS's screen lock and login screen customisation
elementary OS presents two related but separate barriers: the screen lock protects an active session, while the login screen greets someone after logout or restart. Each uses its own settings, so changing one does not automatically restyle the other. Understanding that split is the safest way to personalise elementary OS without weakening access or locking yourself out.
That distinction matters on Australian commutes and in shared workspaces. A laptop left open on a train after leaving Bondi, a computer in a Melbourne laneway café or a hot desk in a Perth office can expose messages, customer records or online banking sessions. A separate account on a Canberra public-library computer adds another boundary, while the 24-hour clock common on Australian work devices should remain easy to read.
Configure behaviour before decoration. Set the account password, blank-screen delay, automatic lock and suspend behaviour first; then add a wallpaper or greeter theme. Keep a recovery route ready, especially on a family laptop or a machine bought through JB Hi-Fi or Officeworks, where the exact elementary OS release may differ.
Understanding the two lock screens
The screen lock is a shield over your running desktop. Your applications stay open and notifications may remain visible, but the session cannot be used until the password is supplied. elementary OS can show the clock and date, offer a return-to-login control and, depending on the release and privacy settings, display notification summaries.
The login screen is the greeter shown by the display manager before a desktop session begins. It normally lists accounts, may offer guest access and carries the image or theme used before a user signs in. Changing the account avatar can affect how that account appears, but it does not alter the greeter's background artwork.
Desktop wallpaper, active-session lock artwork and greeter artwork are three separate visual layers. Treating them as one produces confusing results, particularly after an elementary OS update replaces a themed package. The lock screen protects the person already signed in; the greeter controls what the next person sees.
Configure automatic screen locking
Open System Settings and select Privacy, or Security in a release that groups controls differently, then choose Screen Lock. Set Blank Screen Delay to the point at which the display should go dark and enable Automatic Screen Lock. Where available, also enable locking when the computer suspends. Exact labels vary slightly, so search the settings panel if the wording differs.
For a portable work laptop, a five-minute blank delay and immediate automatic lock are a sensible baseline. Use one or two minutes for a public library or reception computer, and ten to fifteen minutes for a supervised home desktop. Avoid Never on a device that travels; a parked café table or an unattended meeting room should not remain available indefinitely.
Closing the lid should suspend rather than hibernate when you need a quick resume, and the suspend lock should activate first. On a desktop, the inactivity timer does the same job. Check laptops connected to an external monitor because some power settings treat the second display as evidence that somebody is present and postpone blanking.
The usual Super+L shortcut locks an active elementary OS session immediately. Make that muscle memory before a presentation or client call, and test it after changing the keyboard layout. If notification previews reveal meeting names or student information, turn them off on the lock screen in the privacy controls.
Change the lock screen wallpaper
Start in System Settings. Some elementary OS releases provide a Lock Screen Background image chooser beside the wallpaper controls; others expose only the desktop wallpaper. Choose the built-in chooser when present. If none appears, check whether the release uses the standard desktop screensaver setting before installing an extension.
The standard setting can be queried and, when the relevant keys exist, changed from Terminal. Use an image you have permission to display:
gsettings list-keys org.gnome.desktop.screensaver
sudo install -m 644 "$HOME/Pictures/login.png" \
/usr/share/backgrounds/elementary-login.png
gsettings set org.gnome.desktop.screensaver picture-uri \
'file:///usr/share/backgrounds/elementary-login.png'
gsettings set org.gnome.desktop.screensaver picture-options 'zoom'
# Run this only if picture-uri-dark appears in the key list.
gsettings set org.gnome.desktop.screensaver picture-uri-dark \
'file:///usr/share/backgrounds/elementary-login.png'
The zoom option fills the screen without distortion, although a 16:9 image usually works best on a laptop. Lock the session and confirm the result; if the image does not change, that release uses a different setting. The commands apply to the current user, so repeat them for other accounts that need the same artwork. For creative work, this drawing tablet setup explains pointer and tablet behaviour under elementary OS; after pausing a stylus session, use the normal lock action instead of leaving the drawing visible to someone passing your table.
Personalise the LightDM greeter
Recent elementary OS installations normally use LightDM with an elementary greeter, but checking is better than guessing. Run systemctl status lightdm --no-pager and inspect /etc/lightdm/lightdm.conf. Date, time format, keyboard layout and account details are safer places to begin; the account avatar and display name can also be edited in System Settings.
For a deeper theme change, make a backup and clone the installed theme instead of editing package-owned files directly. The following is an example; replace elementary-greeter with the actual folder shown by ls /usr/share/lightdm/greeters:
sudo cp /etc/lightdm/lightdm.conf /etc/lightdm/lightdm.conf.bak
sudo cp -a /usr/share/lightdm/greeters/elementary-greeter \
/usr/share/lightdm/greeters/harbour-greeter
Open the copied folder and read its configuration or stylesheet. Replace the image that the theme actually references rather than dropping a JPEG into the directory and expecting it to appear. Elementary's own theme names and image conventions can change between releases, so the copied theme's documentation is the authority.
To point LightDM at the clone, add greeter-theme=harbour-greeter to the existing [Seat:*] section of /etc/lightdm/lightdm.conf, while retaining the current greeter-session line. Save the file and restart LightDM only after saving your work, because the running session will close:
sudo systemctl restart lightdm
The greeter can also hide manual or remote login choices for a kiosk, although a home laptop may benefit from leaving manual login visible. Use your own workshop or community artwork instead of implying official endorsement. Custom copies are less likely to be overwritten by updates than files inside /usr/share, and the backup gives you a quick way back.
Use profiles, shortcuts and recovery options
Create separate accounts for family members, volunteers or colleagues who use the same machine. Each account can have its own password, avatar, wallpaper and lock-screen preferences, so one user's graphic does not leak into another session. Avoid automatic login on any portable or shared computer, even when the device sits in a locked office.
A practical routine is to lock before stepping away, even for an arvo break, then return and unlock with the same keyboard layout used when logging in. Hide sensitive notification previews, remove private files from the desktop and disconnect shared removable media before handing over a device. Guest access is useful for a short workshop, but the primary account should remain protected.
If a greeter theme prevents login, use a virtual terminal. On most installations, Ctrl+Alt+F3 opens a text login. After signing in as an administrator, restore the configuration and restart LightDM:
sudo cp /etc/lightdm/lightdm.conf.bak /etc/lightdm/lightdm.conf
sudo systemctl restart lightdm
If the backup is absent, inspect sudo systemctl status lightdm and the journal before changing more files. Keep the recovery key for an encrypted disk somewhere secure, and verify that an administrator account exists before altering the greeter on a computer with no physical keyboard.
A polished lock screen should still make the active session obvious, while the greeter should feel like the entrance to the desktop rather than a second wallpaper. Keeping those jobs separate makes the result easier to audit, update and recover, particularly when a community workshop changes its image between events.
The practical takeaway is to make the lock path routine first: choose a short blank delay, enable locking on suspend, rehearse Super+L and confirm that recovery works before adding imagery or a greeter theme.
