Not sure how to change the default no images theme, because the stars client auto-updates those themes, but you could make your own no images xtheme using all the same base images.
You will want to create your own xthemes folder(s) in the pokerstars program folders, similar to this:
C:\Program Files\PokerStars\XThemes\Fozzy@TiltBuster.com\My No Images
*If you have a 64 bit OS, the path will be slightly different.
You will obviously want to name everything for you, instead of me. Something like: C:\Program Files\PokerStars\XThemes\ProsperousOne. You will also want to change all the @tiltbuster.com references in the INI code to something more appropriate for you, such as
Prosperousone@twoplustwo.com.
You should then make 2 new folders inside of that folder named \label and \ctrls
Copy all the files, except the 6 cashierx files from: C:\Program Files\PokerStars\Gx\ctrls to your new \ctrls folder - C:\Program Files\PokerStars\XThemes\Fozzy@TiltBuster.com\My No Images\ctrls
Then copy these 10 files from C:\Program Files\PokerStars\Themes\simple\label to your new \label folder - C:\Program Files\PokerStars\XThemes\Fozzy@TiltBuster.com\My No Images\label
border.a.bmp, border.bmp, borderb.a.bmp, borderb.bmp, seat.a.bmp, seat.bmp, status.a.bmp, status.bmp, statusb.a.bmp, statusb.bmp
Copy the table and background files (fg.bmp, fg.a.bmp, bg.jpg) from: C:\Program Files\PokerStars\GxC:\Program Files\PokerStars\Gx
Here is the code from one of my older no images themes, that I just edited for this example. You will need to add it to the C:\Program Files\PokerStars\XThemes\xthemes.ini file.
Code:
[My No Images@Fozzy@TiltBuster.com]
name=My No Images
copyright=(c) TiltBuster.com 2008
folder=Fozzy@TiltBuster.com\My No Images
base=simple@pokerstars.com
deck=simple