Men are just grown boys.
I've seen just as many profiles of men with only head shots as I have women. Women have to spend money too, this isn't a one sided website where they get free upgraded profiles and men have to pay.
I do notice actually that there have been many many men that not only don't post any kind of picture but they don't fill out their profiles as well. I wonder how we'd know that there was someone worth contacting out there that we wanted to contact us back.
So in conclusion, I think you made a good suggestion, it shouldn't be limited to women only though.
:)