Mirror and rotate an image

Turning and mirroring look like two separate tools, and most editors present them that way: a rotate button, a flip button, and a picture that ends up in some orientation after a few clicks nobody can retrace. They are one family. Four quarter turns, each with or without a mirror, give eight orientations, and every sequence of flips and quarter turns — however long — lands on one of those eight. Flip vertically and then turn right, and you have a diagonal flip. Flip on both axes, and you have a half turn.

So this page shows the eight directly. Each swatch in the grid is your own picture, drawn small by the same engine that writes the file: Original, Mirror, Flip, Both axes, Turn right, Turn left, Diagonal ↘ and Diagonal ↙. Pick the one that looks right and the matrix and its description appear underneath. All eight are exact — whole-pixel moves with smoothing off — so the saved picture holds the same values as the source, rearranged.

1. 1Open the picture. Its EXIF orientation is applied first, so the grid starts from the picture the way your viewer shows it.
2. 2Pick from the eight. Each swatch is your own picture, drawn the way that orientation would leave it: original, mirror, flip, both axes, turn right, turn left, and the two diagonals.
3. 3Or build it from parts. Choose an axis, then a clockwise turn, or use H, V, B and the [ and ] keys. The matrix and a sentence under the controls say which of the eight you have.
4. 4Save. Fit keeps every pixel (a quarter turn swaps width and height). A JPEG can also take the orientation-tag route, which stores the result in sixteen bits and copies the picture data untouched.

A 3024 × 4032 portrait JPEG carrying EXIF orientation 6 opens upright, because the tag is resolved before the grid is drawn. Picking Diagonal ↘ gives a 4032 × 3024 result — width and height swap — with the matrix [0 1 / 1 0]. Saved as PNG, it holds all 12,192,768 pixels with their values unchanged, and reversing the choice reproduces the source exactly. Saved by the orientation-tag route, the file stays the source’s size: the tag becomes 4 and the compressed picture data is copied byte for byte.

• Quarter turns only. Arbitrary angles, straightening and perspective are not offered: they resample, and this page does not.
• Keep original size resamples. Holding the old frame after a quarter turn means scaling the picture down to fit, and the control says so.
• The tag route relies on the viewer. A viewer that ignores EXIF orientation shows the stored picture, untouched. Re-encode or use PNG where that matters.

Why exactly eight?

A rectangle can lie in eight ways and no more: four quarter turns, each with or without a mirror. Every combination of flips and quarter turns lands on one of them — flip vertically then turn right is the same as a diagonal flip, and flipping on both axes is the same as a half turn. The grid shows all eight so you can pick the result instead of working out the steps.

What is a diagonal flip?

A reflection across a line from one corner to the opposite one. The top row of pixels becomes the left column. It is also called a transpose, and it is what you get by mirroring and turning a quarter. Width and height swap.

How do I rotate an image 180 degrees?

Choose 180° under Turn, or Both axes under Reflect — they put every pixel in the same place. The readout names the one you chose; the file is identical either way.

Can I rotate by 45 degrees or straighten a horizon?

Not here. Any angle other than a quarter turn lands between pixels, so the picture has to be resampled, and this site's promise is that it does not. The eight orientations are exact.

Does a quarter turn lose quality?

No pixel changes value. In the default Fit frame, a quarter turn simply swaps width and height. Only "keep original size" resamples, because the turned picture is scaled to fit the old frame — and the controls say so when you choose it.