You guys really think that enforcing a picture will lead to people uploading a picture of themselves? The place will be flooded with pictures stolen from the net, like flickr. I'd love everyone to upload a picture as well, but forcing them is not going to work.
Yep I don't think insisting will help . . .
I just ignore the "profile" and if everybody did the same then they would be pointless.
However, we are all different, joined by a love of things lycra/tight. Letting people on who are not so outgoing initially (I have face pix on my profile)will maybe lead them by example and therefore pictures might appear as they develop their confidence. I was a shy (lonely) boy once . . .