It doesn't seem fair that people first judge you by how you look. But they do. If someone tells you that they are not judgemental toward people they see or meet, then either they're lying or just naive.
Very often in an online environment such as LinkedIn, Facebook or even a dating site, your photo, head shot, profile picture or whatever you decide to call it "is" people's first impression of you. Call me crazy, but they will extract certain opinions or judgements about you in less than a second. Much of it is subconscious. But they will judge if you are friendly, approachable or assertive, or bottom line; if they want to do business with you. According to new research at Bilkent University in Ankara, Turkey and Cornell University, our first impressions of people in photographs influence our perceptions of those people even after we've interacted with them personally. This should be a wake up call to action and fix the situation.
Your photograph is going to be different if you're a corporate attorney than if you are a roofer or a dog sitter. A skilled photographer will know how to lead you in the right direction from colors to wear to what expression and backgrounds are best.
If you have a professional photograph made at all, even if it's not great, will tell a potential client that you care enough about your business to go through the trouble and expense of at least attempting to make a good first impression. If the photograph makes you look friendly, approachable and assertive, then you've hit a home run.
For those who have no photo of yourself on your profile page, you're leaving money on the table. If your photo is terrible, unflattering or the background is unfitting, you're leaving a very definite negative message about yourself that you may never recover from.