Adding a picture to the user login screen

How can I add a picture to the my user loging screen. I am using KDE4 on openSUSE 11. Thanks!

I believe changing the kdm login theme to a custom one with one’s own pictures is not trivial. I have not seen a how to on it. It is possible to change various splash screens:
Custom splash screen - openSUSE

It may not have been implemented in KDE 4 yet; if you have KDE 3, it is Control Centre > System Administration > Login Manager

Thanks for that. I added it to the custom splash screen wiki:
Custom splash screen - openSUSE