How can I change picture in the login screen

Cannot find how to change/add picture to the
login screen?
Any tips?

The OP asks for the login screen not the Lock screen. This program has been useful to me. It is much more stable now than it was, and should be able to change the backgournd wallpaper of your logon screen.

You could go to to settings/accounts/sign-in options and use a picture password (not quite what you are asking for) but it is cool and you can use any picture you like.

TC