ok, so I was looking through the code looking for how the girl images are handled (especially pregnant images)
That code you found just enumerates the different image types, it doesn't determine how they're loaded.
What you're looking for is around line 7633 in cGirls.cpp.
root/
trunk/
BrothelMaster/
cGirls.cppMore specifically:
{"Anal*.jp*g","BDSM*.jp*g","Sex*.jp*g","Beast*.jp*g","Group*.jp*g","Les*.jp*g","Preg*.jp*g","Death*.jp*g","Profile*.jp*g","PregAnal*.jp*g","PregBDSM*.jp*g","PregSex*.jp*g","pregbeast*.jp*g","preggroup*.jp*g","pregles*.jp*g"}
Looking at that, it seems like it might be lumping all pregnant sex images into the initial plain pregnant images; wouldn't "Preg*.jp*g" also cover "PregAnal*.jp*g" and so forth? I'm not 100% on how that particular code actually works, I'd have to dig a bit more I think.
Is the problem you're seeing that pregnant sex images aren't being used?