Please note that I've raised the following KDE Bug Report with respect to the System Settings - System Administration - Login Screen - User Icon File placement:
"Bug 370235 - System Settings - System Administration - Login Screen - KDE 4.14.9 - User Icon File placement": <https://bugs.kde.org/show_bug.cgi?id=370235>
KDE4 Plasma Version 4.14.9 - System Administration Version 4.11.20 - openSUSE 13.2
When a system-wide User Icon for the KDM Login Screen is set-up, the icon file is written to /usr/share/kde4/apps/kdm/ with the file name "faces<user-name>.face.icon".
I am using non-KDE icon files for the system-wide user's login icon.
Renaming the file to "<user-name>.face.icon" and moving it to the directory /usr/share/kde4/apps/kdm/faces/ is the current work-around that I'm using.