Here are some basic things to consider when using a photo on Linkedin:
1. It is not optional. Weird ideas fill a void. If you don't have a photo, then viewers of your profile will use their imaginations to create their own image of you. Leaving people to their imaginations usually is not in your favor. You will inevitably disappoint in person.
2. About disappointing in person, use a realistic image of you that is relatively current. Over ten years? Hair dyed a new color or fell out?  Gained or lost 40 pounds? It is time for a new photo as you will most definitely shock in an in-person meeting. This is definitely a "what you see is what you get" situation.
3. Dress appropriately for the audience and the business demographic you are targeting. If you are looking for business or a job in tech then dressing in a formal dark suit and red silk tie might be off-putting when the business dress code for the company is yoga pants, jeans, and hemp shirts. This is probably the most important tip as to how you are dressed creates a first impression that is hard to erase. Plus, take off your tint-adjusting glasses when outdoors.
4. The setting and pose is a question of relevance. If you are in law enforcement, outdoor sports, or any risky business then a skydiving shot of you at 9,000' might be a great pose . In chartered accounting, banking, brain surgery, maybe not so much. Same could be said for the really cute pose taken at Burning Man or Coachella. Keep your personal life off Linkedin.
5. Look forward at the viewer or towards the center of the screen. This is crucially important now that Linkedin has moved photos to the left side of the screen as you view it. If your body and head are facing out to the left as well, the portrait image creates an unconscious psychological dissonance with the rest of the layout.
6. In the same vein, the background color and view can add or detract. An all white background ranks higher than the ubiquitous corporate photo gray or worse Hollywood black. White is young, edgy and won't fight with your Linkedin background banner that hopefully, you have customized (a topic of another article).
7. Finally, look happy...not cool, inviting, engaging, business-like, professional, or a leader (whatever that is),  Just be happy when the shutter snaps. Happiness is contagious and welcoming to everyone. 

​Trust in the portrait-making process,and hire a professional photographer, not your wife or partner. Pick a decent background and outfit. Don't worry, be happy..

Sometimes it seems nigh impossible to move the dial on an established, but obsolete, traditions like applying to a job posting and spreading your resume all over the Internet to find a job. The article below confirms this with statistics.

It doesn't matter that more management and executive level professionals get hired through their networks than through job postings annually.  That executive search consultants account for less than 10% of the executive positions placed annually in the USA.

It doesn't matter that even before anyone sees your resume, they will see your social profile first. And, even if they get your resume first, they will look you up on Linkedin and search you out on Google to get tmore depth about you. And when they find something they don't like online, more than 50% of the recruiters surveyed say they drop you from their candidate list.

People persist in using their resumes to apply to job postings.  Why? Because it has always been done that way and because when it comes down to the actual interview, HR wants some kind of document to provide to hiring managers for reference. 

When will the transition to social profiles and personal websites take hold? If Linkedin has anything to say about it, it will be sooner not later.  

LinkedIn survey details 'new norms at work'
Matt Kapko May 8, 2015 
 
A new survey of 15,000 LinkedIn users with fulltime jobs, 1,000 of which reside in the United States, draws some interesting conclusions while also reinforcing common perceptions about the "new norms" within the modern U.S. workplace. 

More than a quarter (26.6 percent) of the people from the United States who were surveyed said it's important to maintain separate social media profiles for work and personal. One in five U.S. respondents (20.5 percent) said they make initial impressions based on a person's online profile picture. And one in 10 respondents said they worry about what their colleagues may think of them based on content they shared on social networks that may not seem professional, according to the survey, which was conducted by Censuswide for LinkedIn during the first week of April.

Catherine Fisher, LinkedIn's career expert, says the findings stress the fact that people need to be mindful of how they portray themselves on social media. 

The U.S. responses also highlight notable difference between women and men in the workforce. Almost a third (30.9 percent) of women respondents said they are friends with colleagues on non-professional social networks, while only 16 percent of men said the same. Nearly a third of the women (32.5 percent) feel as though they're judged by what they wear to work, and more than a quarter (26.8 percent) said they believe men have it easier when it comes to the threads they don at work. And more than four in 10 women (41.6 percent) said they tend to dress up more when they have meetings during the day, while only 25.5 percent of the men step up their dress for meetings.

Work experience, education and volunteer history are the three top factors U.S. users weigh to gauge a colleague's LinkedIn profile, according to the survey.

More than one in five (21 percent) of those surveyed from the Unites States said it's more appropriate to self-promote now on social media than in years past. Almost 13 percent said they feel more comfortable sharing their opinions on industry matters via social networks, and nearly 9 percent think doing so is a great way to raise their professional profiles. 
 
Perhaps most surprising of all is that only 12.8 percent of U.S. respondents think a good LinkedIn profile is just as important as a good resume.