I can confirm that for my case - when I (female) removed my picture from Okcupid, it had the (desirable, then) effect that I didn't get any messages whatsoever anymore, over the space of ~6 months. I might have gotten a non-zero amount if I hadn't stated on my profile that I wasn't looking for relationships at the time, but even with that clear statement I still got messages every once in a while during the time I had the picture up. I didn't try experimenting with a more/less attractive picture.
I got the impression that many people just look at the profile and don't even check the relationship status at the top of the profile.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
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