Mirror your faceSee both sides of your face

Faces are close to symmetrical but never exactly. One eye sits a little higher, the mouth lifts more on one side, the parting of the hair pulls the eye one way. A mirrored face takes one half of a portrait and replaces the other half with its reflection, so every one of those small differences is doubled on one version and erased on the other. Do it with each half in turn and you get two faces — left-left and right-right — that often look like siblings rather than the same person.

This page is the mirror-half tool opened for portraits. Three things are different from the general page: the join is softened by two pixels by default, because skin hides a soft seam far better than a hard one; the line can be tilted to follow a head that leans; and an optional face finder can propose where the midline runs. Without the finder, everything works by hand.

1. 1Open a portrait. A front-on photo works best: both eyes visible, face roughly square to the camera. The page opens with an upright mirror line down the middle, keeping the left half of the picture.
2. 2Put the line on the midline. Drag the line on the picture so it runs between the eyes and through the middle of the nose and mouth. If the head leans, use Tilt. Or press Find the midline to have a small on-device face finder suggest the line.
3. 3Swap halves to compare. Keep the left half for one version, the right half for the other. Saving both gives you the left-left and right-right faces side by side in your downloads.
4. 4Save. PNG keeps the result exactly as drawn. The readout states whether the line was upright (exact) or tilted (resampled).

A 1200 × 1600 selfie with the eyes found at (520, 700) and (700, 688) and the mouth corners at (560, 1000) and (668, 993) has an eye line falling 12 px over 180 px, so the suggested tilt is −3.8°. The line runs through the average of those four points, (612, 845), perpendicular to the eye line; where it crosses the middle row (y = 800) it sits at x ≈ 609, which the page shows as 50.7 % across. The saved file stays 1200 × 1600. Because the line is tilted, the readout says the result is resampled; set the tilt to 0 and the same photo mirrors exactly about column 608.

• A composite is not a measurement. Light from one side, a small head turn or a wide-angle lens all make the halves differ. The composite shows the picture, not the anatomy.
• A tilted line resamples. An angled line does not follow the pixel grid, so the reflected half is interpolated (bilinear). Upright lines are exact.
• The finder only suggests. It proposes a line from five points — eyes, nose, mouth corners — and can miss profiles, sunglasses and very small faces. You decide where the line goes.
• The frame stays as opened. With a tilted line there is no clean 'twice the half' frame, so the output keeps the photo's own size. Where the reflection would need pixels from outside the photo, the original shows through.