I think you need to check someone out from afar to know if you find them attractive. Sometimes it evolves over time. The way someone moves, talks, a certain look they give, that's what attracts me, not a static picture. That's where internet dating doesn't work for me, unless you're a wow factor I won't give you the time to be that, I move on to the next. In real life that can develop before you go out with someone, time to think. My relationships have always been with people I've met gradually who have grown from a spark to me really wanting them. That takes time. I've never had a relationship with someone I met in a bar/club/one night kind of thing. And I doubt I will find that on here, but it fills a gap in my life.
I would always imagine the person I was with when they are old and I am old and would I still be happy with them, it's a good indicator to me.