Alright, I think I found the character graphics
>\assets\GLOBAL\ui\imagesets\cards
I'm not sure if this is all the girls though. It should be, but it doesn't seem like there are enough girls here. For example, I don't see Tuonel of Night. I wonder if there are more images in another folder somewhere. There are also some girls who look like GL either never got them, or they might be prototypes of other characters, or maybe I just don't remember them.