[Gprename-users] How to keep file extension?

[Edwar C. <edw...@gm...>]

Hello, is this mailing list active? if so, I downloaded gprename to 
remove some unnecessary characters from the end of the names of some 
files, e.g. Myfile-g0t9j89.jpg
To remove these characters from the end of the file I'm using a negative 
number in "Delete between" and a big number in "and" (like 500)
I would think that to get "Myfile.jpg" I'd need to delete 7 characters 
from the end, however I end up with Myfile-g0t9 instead because gprename 
it's also removing the extension and dot.
How do I tell gprename to leave the extension alone and only start 
removing from the last character in the actual name.
Thanks