I think you mean adverse selection, not moral hazard.

Also, I would note that I know some very attractive women who do not put profile pictures on dating sites because they don't want to attract too much attention because of how they look. So this could mitigate the adverse selection problem.

When I first heard that some women did this, I started messaging women who had no pictures (or pictures that did not show what they looked like). Not long after, I met my wife, who would have been mobbed with messages had she put up a photo that showed what she actually looks like. I was the first and only person she dated online.