When I was still on OKCupid, I once wrote a Chrome extension to hide the pictures. I found that I had, in general, a much better experience with the site - I'd actually read people's profiles, I sent better messages, and I got more responses. I eventually gave up on it when a site redesign changed some of the #ids I was depending on and I didn't feel like revamping the code. But interestingly, my eventual girlfriend had terrible pictures - the grainy, multiple-people-in-the-background sort you're never supposed to put on a dating site. Setting up our first date, she was like "We don't need to exchange numbers, you know what I look like", and I was like "Actually, I'm not sure I do, here's mine." (Okay, I didn't actually tell her her pictures were terrible until we'd been dating for six months or so, but that was the general sentiment.)

I think it's one more example of when people's emotions and desires lead them to suboptimal outcomes. Most of the cues we associate with beauty and sexual desire evolved back in the savanna when health and fertility were very real risks; being able to pick up on which potential mates would be able to carry healthy offspring to term and nurture them until adulthood was very important then. Nowadays, the far greater risk is that you'll hate each other and fight all the time, but this has only been a concern since people started living long enough and in close enough proximity to care.