Change the Screen Lock Icon

The default system icon that selock uses is the  logo and is located in the file ACInstallDir/data/admin/Selogo.xpm
capamsc141
The default system icon that selock uses is the 
PAM Server Control
logo and is located in the file ACInstallDir/data/admin/Selogo.xpm
To select an icon of your own choice, replace this file.
The icon file must be in XPM version 3.3 format.