Flip horizontally or vertically: what changes
A flip swaps two sides of a picture and leaves everything else alone: the size, the colours and every pixel stay what they were.
| Flip | What it does | How to tell |
|---|---|---|
| Flip horizontally | Left and right swap, like in a mirror | Text reads backwards |
| Flip vertically | Top and bottom swap, like a reflection in water | The picture stands on its head |
| Both | The same as a half turn (180°) | Nothing is mirrored |
Flipping is not rotating
A rotation turns the picture around its middle, the way you turn a sheet of paper. A flip turns it over, the way you turn a page. No rotation makes a mirrored picture, and no flip turns a portrait into a landscape. That is why the tool has both: the two large buttons flip, the two small ones turn by a quarter.
Why a selfie looks mirrored, or wrong
The front camera of a phone shows you a mirror image while you take the picture. Some phones save it that way; others turn it round to how other people see you, which is why a selfie can look unfamiliar afterwards. One horizontal flip switches between the two: the face you know from the mirror, and the one everyone else knows.
What to check after a flip
Anything that has a side gives a mirrored picture away: writing on a sign or a T-shirt, a logo, a watch on the wrong wrist, a parting on the other side, a car with the steering wheel on the passenger side. If the picture has none of these, nobody can tell. A flip is also the quick way to make a face look into the page instead of out of it.
Does flipping reduce quality?
The flip itself loses nothing: the same pixels in another order. A PNG is saved without loss. A JPG or a WebP has to be compressed again, which the tool does at high quality to keep the difference out of sight. Data stored inside the file, such as the place and the camera, is not carried over. Only a very large picture changes size: one longer than 4096 px on a side is scaled down to that, and the tool tells you so.