As an online dater, I have to tell you I am amzed at the pics people put up on their profiles. Like mass murdering, pscho talking-to-themselves-in-the-basement no smile fish eyed pics. I steer faaaaaaar away from those... I agree you can't tell everything but you have to wonder. If that is the pic they chose, what ones did they pass over...
I am not photogenic at all, but at least I look like I would be friendly enough in all the pics I post on my online dating profiles.
I think that is a combination of their picture and their comments. Some people have fake pictures and it's totally lame and their comments are stupid or very "do you like penis" type of comments. Others have a sense of humor or are really cool people and their profile pics are kinda funny or very obvious about them (they aren't pretending to be anyone else) @dontdropit @red_dragon as an example.
And some people have their real pictures and have all their posts anonymous so you really can't tell what kind of personality they have.