In in online dating world, a good photo is priceless. It's the first thing someone will see when looking at your profile. On some sites, it's all about the photo, with very little information to go along with with.
I'm not one to judge solely based on looks, but a good picture will help create a "spark", that little something that makes you stop and look twice at someones profile.
Some people look exactly like their photos, which I think is a good thing! For good, or bad.. when you meet someone online, you see their photo, you begin to imagine that person as you are chatting with them. When you finally meet in person, there are no surprises. I met one guy online, who looked like a late 20-something alterna-snowboarder dude. When we went in person, he was a 40+ man who looked like a troll! How could I have gotten such a wrong visual impression of someone? I've also had conversations with guys who have a few photos on their profiles, showing some variety and range.. but realize later that the range of photos they were promoting was from 10 years ago.
I try to keep my photos current. I'm always taking new photos, and updating my profiles. I was just stopped in public last night, by a guy who recognized me from one of my dating profiles. I must look like my photos for this guy to see me in a crowd of a thousand people, and say "Hey, That's the girl I emailed 2 weeks ago".
I only wish that more men took the time to make sure they have a decent photo, and actually look like the photo they are promoting.