Images
Every user on the system is represented by a image. The image for the user is 
kept in a file called $(KDEDIR)/share/apps/kdm/pics/users/$(USER).xpm.
If the user doesn't have such a file the file
$(KDEDIR)/share/apps/kdm/pics/users/default.xpm will be used instead.
To assign a new image to a user just selct the user in one of the listboxes 
and:
Select users
If you choose not to show users, the users will have to write their user name 
at the login window. If you choose to show users they can simply click on an 
icon representing themself, enter their password an click "Go".
The pages contains three listboxes. The large listbox on the left shows all 
the users on the system which we may presume could be a genuine user.
The top rightmost listbox shows the slected users and the bottom rightmost 
listbox shows the users we don't want displayed in the login window.
To move a user from one listbox to another you click on the username in the 
listbox and selects ">>" to move the user from the leftmost box the the 
rightmost box - or "<<" to move the user from the rightmost box to the 
leftmost box.
The users to show can be selected in two ways: