Oh, Vector, I use it as well.To be honest, i can't remember if it was a mod or just an option in the game itself. But there was the possibility to either activate generic pics for your slaves or polygon graphics. The advantage of those polygons was, that there was different haircolors, piercings, skin color, clothing, amputations and even the shape of the body itself. Not very pretty, but the graphics were more accurate in showing how you "shaped" your slaves.
It helped a lot in managing the slaves when you wanted to form them according to the dominant beauty rules, since you were able to see if the slaves fit or not by just looking at them, instead of (just) reading the text.
EDIT: I checked the Free Cities website, it was called VECTOR ARTPACK. The MEGA-link is still active