I have the same problem with kde screensaver, I prefer the older xscreensaver. And some screensavers from kde are buggy.
So I use xscreensaver!!
I also have Only one screensaver, don't remember what it does.
choose an image randomly, put your directory , and put all your girlfriends image inside
then check with File->Screensave now (I don't know the exact name, I'm in french language)
Not sure it answers your questions but for me it works as expected.