Modern marketing experts figured out a lot about human nature to elevate the corporate brand status and sell more stuff through e-commerce sites.
The same human nature is at work on dating sites (In fact, I started applying marketing principles to private life when I signed up for Yahoo! since then the dating sites evolved and became a lot more like a marketing project).
People use pictures to filter out options quickly because reading the profile or message takes too much effort.
People do the easy things first and check out your pictures before reading your message.
Stellar photos for your online dating profile(s) are key in attracting a potential match.