How can I change an image, displayed when client computer is locked remotely?

Version 9 and 8 by default uses a graphics image instead of text notification, used in previous versions. To replace an image or edit it, please open the following file:
C:\Program Files\Net Control 2\locked.jpg
in any graphic editor, for example Windows Paint, edit it and save using the path above.

For versions 7.xx or below:

The text of this message may be changed remotely from Administrator computer or manually on each user computer:

1. On User computer:

click icon in the System Tray;
click menu command "Configure"

or

2. Remotely, on Administrator computer:

select user computers,
apply menu command N -> Options -> Remote Computer Options;
configure all necessary settings (not configured settings will be reset to defaults);

3. on "Custom Text Messages" tab, edit the text in "Computer is locked" field;
click OK button.