Models are attractive people. The terms works for both sexes. Ask yourself why there has to be any reference at all to the fact that the pictures are of females. Your placeholder image leaves little doubt about that fact.

I'm trying to get an idea across to you: it isn't okay to use women as sex objects in public conversation like your site. It isn't okay to single women out, even as "nice girls." Both your image and your text make it about their sex and sexuality. Use whatever images you like on your own computer, but when it comes time to share with the internet, have some tact. Lie a little and choose something less offensive when sharing a story like this. A quick flickr search found the following pictures of attractive, presentable women:

* http://www.flickr.com/photos/jamespicsatflickr/3531188607/ * http://www.flickr.com/photos/jamespicsatflickr/4327536639/ * http://www.flickr.com/photos/chamberimages/4489201274/

Without any emphasis on women in your text, you'd still have a great contrast to the photo of your cofounder with any of these images, with none of the sexual overtones.

I wouldn't take the time to respond if I didn't care—you have some truly great design work that deserves to be shared. I'm trying to help you see the parts of it which are unacceptable, so you know not to make the same mistake next time.

And for now, seriously, just remove "nice girls". It's awkward English, regardless.