LinkedIn is a professional platform
Look like yourself
No wedding photos
No convict-like photos
Follow the rules
Your photo must reflect how you look when you're meeting with a prospect for the first time. (Consistency is critical.) You likely don't show up with your dog or a favorite family member, so why would you include them in your profile picture?
If you wear glasses, wear glasses. If you dress more formally, dress formally. As a best practice you should have a recent photo. (Every two years makes sense unless you've changed dramatically.)
Don't use a photo of you from a wedding, or a barbecue, or family event just because you looked fabulous. Never use one of you where you've cropped out the other person. There are way too many distended arms hanging around people's shoulders! Creepy.
Ask a family member, colleague or a friend to help. Pay attention to the background, no trees growing out of the back of your head.
Do not stand directly in front of a wall. A diffused background with some depth is preferable. Avoid direct sunlight and ask your photo-taking friend to ensure there aren't any odd shadows.
Your photo can be removed by LinkedIn if your profile image doesn't include your likeness or a headshot photo. Some examples of photos that shouldn't be used are logos, landscapes, words, animals, etc.
LinkedIn Profile Pcture