When a business owner hands you their card or you drive by their billboard and it has a genuine but professional photograph on it instead of a white backdrop school picture feel, we feel more connected to them because its unique and honest to who they are.
When you go to a businesses website and they have a gallery of real life in action photographs instead of stock photography, displaying who they are and how they work, we feel connected to them because we all want to hire a sincere business.
Use a portrait that your potential clients will see and think how genuine. Don't be one in the same when your business isn't!