As someone who doesn't create girls, I vote against the subfolder idea.
Practical reason: we'd need to change the image loading code *again* (don't know how big a deal this would be), and we'd need to either maintain legacy support or code a converter to parse every girl's pics and sort them into directories (probably could be done with a batch script).
Selfish, changes-would-make-my-life-harder reason: I check every image in every girl pack I download for image quality, artistic quality, and general hotness factor. Currently, I can scan images and toss any rejects relatively quickly. Breaking everything out into 9+ directories would at least double, if not triple or quadruple, the amount of time it takes me to sort through everything.