---
title: "Rotate or flip an image in C#"
url: https://recursiveai.org/oneimage/cookbook/rotate-flip-image/
description: "Rotate an image 90 or 180 degrees, by any angle, or flip it horizontally or vertically in C#. Runnable code with OneImage, on any OS."
version: "1.10.4"
---

# Rotate or flip an image in C#

Load the image, call `Rotate` with an angle in degrees, clockwise, or `Flip` with an axis, and save. Multiples of 90° are exact pixel moves; other angles grow the canvas to fit the turned picture. The program below uses a landscape crop of NASA’s “Blue Marble” photograph (public domain).

```shell
dotnet new console -o RotateImage && cd RotateImage
dotnet add package RecursiveAI.OneImage --version 1.10.4
curl -L -o photo.jpg \
  https://images-assets.nasa.gov/image/as17-148-22727/as17-148-22727~orig.jpg
```

OneImage needs the .NET 10 SDK. Put this in `Program.cs` and run `dotnet run`:

```csharp
using OneImage;

// A 1000x600 landscape crop, so the turns show.
Image photo = Image.Load("photo.jpg").Resize(width: 1000, height: 600, fit: Fit.Cover);
Console.WriteLine($"photo: {photo.Width}x{photo.Height}");

Image quarter = photo.Rotate(90);                   // clockwise
Image upsideDown = photo.Rotate(180);
Image mirrored = photo.Flip(FlipAxis.Horizontal);   // left to right
Image tilted = photo.Rotate(15, background: new Rgba32(255, 255, 255, 255));

quarter.Save("rotate-90.jpg");
upsideDown.Save("rotate-180.jpg");
mirrored.Save("flip.jpg");
tilted.Save("rotate-15.jpg");

Console.WriteLine($"rotate-90.jpg: {quarter.Width}x{quarter.Height}");
Console.WriteLine($"rotate-180.jpg: {upsideDown.Width}x{upsideDown.Height}");
Console.WriteLine($"flip.jpg: {mirrored.Width}x{mirrored.Height}");
Console.WriteLine($"rotate-15.jpg: {tilted.Width}x{tilted.Height}");
```

```text
photo: 1000x600
rotate-90.jpg: 600x1000
rotate-180.jpg: 1000x600
flip.jpg: 1000x600
rotate-15.jpg: 1122x839
```

A 90° turn swaps width and height. The 15° turn grows the canvas to the turned picture’s bounding box and fills the corners with `background:` (transparent by default, which JPEG can’t store, hence white here). Use `-90` or `270` to turn counterclockwise, and `FlipAxis.Vertical` to flip top to bottom.

## Phone photos that come out sideways

If a photo looks right in a viewer but sideways after your code saves it, don’t rotate by hand: its EXIF orientation tag wasn’t applied. OneImage applies it when it loads, so a plain `Load` and `Save` already writes it upright. See [Fix EXIF orientation](https://recursiveai.org/oneimage/cookbook/fix-exif-orientation/).

## Limits

- **JPEG is re-encoded.** Even a 90° turn decodes and encodes the JPEG again, so it isn’t lossless. Save as PNG to keep the pixels exactly.
- **Arbitrary angles resample.** Edges are smooth but slightly soft; pass `expand: false` to keep the original canvas size and crop the corners.
- **Animations** turn every frame.

`Affine` and `Perspective` cover skews and keystone correction; see the [guide](https://recursiveai.org/oneimage/docs/guide/#operations).