Found it! The app is "gdmphotosetup". I can't remember if this is installed by default. (Having a good day aren't I?)
I added that app into my lxdecc script (i.e. /usr/bin/lxdecc) (no wonder I couldn't remember the config file for it) as a new tab "Personal". This is included below if anyone thinks its of interest.
ted
#!/bin/sh
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Library General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
#-------------------------------------------------------
export TEXTDOMAIN=lxdecc
export TEXTDOMAINDIR="/usr/share/locale"
# Start main program
export lxdecc='
<window title="Control Center" icon="/usr/share/icons/gnome/32x32/actions/application-exit.png" window-position="1">
<vbox>
<notebook labels="Appearance Settings|System|Personal">
<vbox>
<frame>
<hbox>
<vbox>
<hbox>
<button>
<input file>"/usr/share/icons/1.png"</input>
<action>/usr/bin/pcmanfm --desktop-pref --set-wallpaper= &</action>
</button>
<text use-markup="true" width-chars="17">
<label>'$"Set Wallpaper"'</label>
</text>
</hbox>
<hbox>
<button>
<input file>"/usr/share/icons/2.png"</input>
<action>obconf &</action>
</button>
<text use-markup="true" width-chars="17">
<label>'$"Configure Openbox"'</label>
</text>
</hbox>
<hbox>
<button>
<input file>"/usr/share/icons/cursor_ring_icon.png"</input>
<action>lxcursor &</action>
</button>
<text use-markup="true" width-chars="17">
<label>'$"Change Your Cursor Theme"'</label>
</text>
</hbox>
<hbox>
<button>
<input file>"/usr/share/icons/3.png"</input>
<action>lxappearance</action>
<action>lxpanelctl restart &</action>
</button>
<text use-markup="true" width-chars="17">
<label>'$"GTK & Icon Theme"'</label>
</text>
</hbox>
<hbox>
<button>
<input file>"/usr/share/icons/4.png"</input>
<action>xscreensaver-demo &</action>
</button>
<text use-markup="true" width-chars="17">
<label>'$"Screensaver Settings"'</label>
</text>
</hbox>
<hbox>
<button>
<input file>"/usr/share/icons/6.png"</input>
<action>pcmanfm --show-pref=1 &</action>
</button>
<text use-markup="true" width-chars="17">
<label>'$"PCManFM Settings"'</label>
</text>
</hbox>
<hbox>
<button>
<input file>"/usr/share/icons/lxautostart_32.png"</input>
<action>lxautostart.sh &</action>
</button>
<text use-markup="true" width-chars="17">
<label>'$"LX-Autostart Settings"'</label>
</text>
</hbox>
<hbox>
<button>
<input file>"/usr/share/icons/5.png"</input>
<action>lxpanelctl restart &</action>
</button>
<text use-markup="true" width-chars="17">
<label>'$"Refresh Panel"'</label>
</text>
</hbox>
</vbox>
</hbox>
</frame>
</vbox>
<vbox>
<frame>
<hbox>
<vbox>
<hbox>
<button>
<input file>"/usr/share/icons/7.png"</input>
<action>gksu /usr/bin/gdmsetup &</action>
</button>
<text use-markup="true" width-chars="17">
<label>'$"GDM Settings"'</label>
</text>
</hbox>
<hbox>
<button>
<input file>"/usr/share/icons/file_tools_section.png"</input>
<action>gksu -l /usr/bin/pcmanfm &</action>
</button>
<text use-markup="true" width-chars="17">
<label>'$"File Manager Superuser Mode"'</label>
</text>
</hbox>
<hbox>
<button>
<input file>"/usr/share/icons/8.png"</input>
<action>gksu -u root /usr/sbin/synaptic &</action>
</button>
<text use-markup="true" width-chars="17">
<label>'$"Install Software"'</label>
</text>
</hbox>
<hbox>
<button>
<input file>"/usr/share/icons/drakconf.png"</input>
<action>gksu /usr/sbin/drakconf.real &</action>
</button>
<text use-markup="true" width-chars="17">
<label>'$"PCLinuxOS Control Center"'</label>
</text>
</hbox>
<hbox>
<button>
<input file>"/usr/share/icons/9.png"</input>
<action>lxinput &</action>
</button>
<text use-markup="true" width-chars="17">
<label>'$"Mouse&Keyboard"'</label>
</text>
</hbox>
<hbox>
<button>
<input file>"/usr/share/icons/10.png"</input>
<action>lxsession-edit &</action>
</button>
<text use-markup="true" width-chars="17">
<label>'$"Session Settings"'</label>
</text>
</hbox>
<hbox>
<button>
<input file>"/usr/share/icons/11.png"</input>
<action>lxrandr &</action>
</button>
<text use-markup="true" width-chars="17">
<label>'$"Monitor Settings"'</label>
</text>
</hbox>
</vbox>
</hbox>
</frame>
</vbox>
<vbox>
<frame>
<hbox>
<vbox>
<hbox>
<button>
<input file>"/usr/share/icons/10.png"</input>
<action>gdmphotosetup &</action>
</button>
<text use-markup="true" width-chars="17">
<label>'$"Login Face"'</label>
</text>
</hbox>
</vbox>
</hbox>
</frame>
</vbox>
</notebook>
<hbox>
<button>
<label>'$"Close"'</label>
<input file>"/usr/share/icons/12.png"</input>
<action>EXIT:close</action>
</button>
</hbox>
</vbox>
</window>
'
gtkdialog --program=lxdecc
unset lxdecc
