Are you sure that the FaceSource line is uncommented?
And that your theme is Bela?
Theme=/usr/share/apps/kdm/themes/Bela
Sorry for going for the obvious, but you never know...
Moreover, root's image disappeared from login screen
That might have something to do with the HiddenUsers parameter. Comment the line that says that. In my file I have HiddenUsers=root, but you should comment that so that you get it displayed.
But root's image showed up on login screen, and user's - not
What is strange is that the user's name doesn't even show up for you to click on it.
Maybe something here:
# Enable user list (names along with images) in the greeter.
# Default is true
#UserList=false
# User selection for UserCompletion and UserList:
# "NotHidden" - all users except those listed in HiddenUsers
# "Selected" - only the users listed in SelectedUsers
# Default is NotHidden
#ShowUsers=Selected
# For ShowUsers=Selected. @<group> means all users in that group.
# Default is ""
#SelectedUsers=root,johndoe
# For ShowUsers=NotHidden. @<group> means all users in that group.
# Default is ""
HiddenUsers=root
# Special case of HiddenUsers: users with a non-zero UID less than this number
# will not be shown as well.
# Default is 0
MinShowUID=500
# Complement to MinShowUID: users with a UID greater than this number will
# not be shown as well.
# Default is 65535
MaxShowUID=65000
What you want is for the UserList, ShowUsers, and HiddenUsers lines to be commented so that you go with the defaults and it shows you both root and the users. The UID lines shouldn't be the problem, unless your user has a weird user id.