One photo, facing the camera. A face landmarker measures each side of your face separately, so the answer comes from the measurement rather than from an opinion about the picture.
What works
Facing the camera, head level
Your face reasonably large in frame
Even light, nothing across your face
Any expression, as long as it is natural
Head turned to one side
Head tilted over
Sunglasses, or hair across an eye
Taken from across the room
Both sides of your face are in the same frame, so they share the light, the lens and the moment. That is what makes a difference between them a fact about your face rather than about the photograph.
Why one side of a face photographs better than the other
Almost nobody is symmetric. One eye usually sits a little more open, one corner of the mouth lifts further than the other, the nose leans a few degrees, and most people part their hair away from one side. None of that is visible in a mirror, because a mirror shows you the version you have looked at every day of your life. A camera shows the other one, and it freezes a single five-hundredth of a second of a face that people normally see moving. That is why the photograph disagrees with the mirror, and why the disagreement is not vanity.
Why one photograph is better than two
The obvious way to compare your sides is one photo of each. We built that first, and it mostly refused to answer. Two photographs taken minutes apart differ in lighting, distance, chin height and expression, and those differences are far larger than facial asymmetry, so a verdict risks being about the photographs rather than about the face. In a single frontal frame both sides share the same light, the same lens and the same instant. There is nothing left to confound, and nothing to retake.
What is actually measured
A face landmarker reports each side separately: how open each eye is, how far each corner of the mouth lifts, how much each eye squints. Those are numbers rather than impressions, and they are shown to you next to the verdict so you can see what it was built from. Differences below a small threshold are ignored, because a landmarker will always report some gap and a verdict built on noise is worse than no verdict at all.
This is not a looks rating
The question is which side a camera renders more clearly, the same question a portrait photographer answers when deciding which way to turn a sitter. It is not a ranking of faces, and the advice never covers surgery, fillers, weight, or reshaping a feature. The standing instruction behind everything CMeIn makes is do not beautify, redesign, age-shift, slim, widen, or change the face.
If the sides measure evenly
That is a real answer and a common one. It also happens when two findings point opposite ways: one side can carry the more open eye while the other carries the stronger half of the smile, and at the level of a whole side those cancel out. When that happens the individual measurements are still shown, because they are more useful than the verdict.
For what to do with your body rather than your face, where to put your hands is the practical version and picturemaxxing is the argument behind it. For a verdict on the photos you already have, use the free dating profile review. To fix the pose inside a photo you own, Pose Maxing does that and leaves the place, the clothes and the face alone.