Hi! I think this is a long standing issue. On System Settings - Desktop Behavior - Screen Locking - Appearance, if you choose picture of the day, you get no options at all. I believe I've read somewhere that's because the lock screen has very limited access, so no internet access at all. Which is fine and all, but I'd still like to get the images updates, if it's in the background while already logged in.

The previous solution involved symlinking $HOME/.cache/plasmashell/plasma_engine_potd/ directory to $HOME/.cache/kscreenlocker_greet/plasma_engine_potd/

This no longer works, as the target kscreenlocket_greet no longer exists. After launching the applet from the console, I think the updated path is /usr/share/plasma/wallpapers/org.kde.potd
However, this holds a different kind of configuration files, plasma_engine_potd holds a single "bing" binary file, while org.kde.potd seems to have several qml configuration files. How can I get the login and lock screen to display the picture of the day?

Thanks!

Even when ~/.cache/kscreenlocker_greet folder not exists, you can create it manually, and make symlink ~/.cache/kscreenlocker_greet/plasma_engine_potd pointing to ~/.cache/plasmashell/plasma_engine_potd - this works well for me on KDE Plasma 5.18.2.