The LinkedIn Smile
Surprisingly, your profile picture can determine if you will be offered a job or not. One of the contract jobs I won, the hiring manager candidly told me after I was hired that one of the reasons I was chosen was because of my profile picture. I was in shock. You mean that bighead of mines with the glistening forehead and my large teeth? Why thank you!
Over the years, I mastered and figured out what will win me over upon first impressions and have chosen that for my profile photo over and over again. People naturally want to smile and laugh. This can be portrayed in one single photo. In addition, a story can be told about you before the review of your work history commences. For example, the hiring manager mentioned that I looked like a "friendly guy to work with" just by one picture. That was the story I told in my photo and that they believed could come true if we worked together. Lastly, I suggest that you make the colors in your photo vibrant and colorful but without it looking like a Skittles commercial.
I say all of this to say, 'Let your personality shine through your profile photo!' The more of your character being shown in your photo, the more authentic you will portray to hiring managers and recruiters.
Cheers to pimping!