I just checked it...it is for 1024x768. If you want to use it at a higher res, you need to open the Logon Studio editor, click on "Center Panel" on the right side, then down towards the bottom click on "Style" and you should see a dropdown arrow. Click it and set to stretched, save and apply.
Then close the LS editor, go to the logon folder, open the uifile, and change line 14 from this:
background: rcbmp(100,6,#0,0,0,1,0);//rcbmp(100,6,#FF00FF,0,0,1,0);
to this:
background: rcbmp(100,6,#FF00FF,0,0,1,0);//rcbmp(100,6,#FF00FF,0,0,1,0);
Save the uifile and apply the logon and it should be fine.
Don't open the logon in the LS editor after that or it will change the uifile back to the default settings.