How to Choose a LinkedIn Profile Photo
LinkedIn photos fail in a narrower way than dating photos. There is really only one slot, most people will see it at about the size of a postage stamp, and the bar is competence rather than charm.
That makes it easier and it also makes the common advice mostly wrong.
You do not need a professional headshot
You need a photo that reads clearly at thumbnail size. A studio headshot does that well. So does a good photo taken outdoors on a phone in reasonable light.
What separates them is not the camera. It is whether your face is large enough in the frame, whether the background is quiet, and whether the light is coming from in front of you rather than behind.
If you have a decent photo from a conference or a friend's wedding, cropped in, it will likely outperform a stiff studio shot where you look like you are waiting for someone to tell you it is over.
The thumbnail test
Shrink the photo until it is about the size of your thumbnail. Can you tell it is you? Can you read the expression?
Most LinkedIn photos fail here for one of two reasons. Either the face is too small in the frame because the photo was cropped from a wider shot, or the background is busy enough that the eye does not know where to land.
What actually moves the needle
Face size. Head and shoulders. If you can see your knees, crop in.
Background. Quiet beats interesting. A plain wall, a blurred outdoor scene, anything that does not compete.
Light on your face. Facing a window is the cheapest good lighting available.
Expression. Something between neutral and a real smile works for most people, though a straighter, more serious expression reads fine in senior and technical roles.
Recent. Within a couple of years. Meeting someone who looks meaningfully different from their photo is a small awkwardness you can avoid for free.
What does not matter as much as people think
Whether you are wearing a suit. Whether it is black and white. Whether it was taken by a photographer. Whether you are looking directly at the camera.
These get a lot of attention and they are mostly downstream of the things above.
How Topit approaches it
Topit ranks the same batch differently for LinkedIn than for anything else. It weights the things that carry at small sizes: how much of the frame your face occupies, how the light falls, and how the expression reads.
Your best dating photo and your best LinkedIn photo are rarely the same picture, and running both contexts on one batch tends to make that obvious quickly.
It also explains its picks, which matters more here than elsewhere. When there is one slot and you disagree with the ranking, you want to know what it was weighting so you can decide whether you disagree with the weighting or with the photo.