---
title: "Crop an image in C#"
url: https://recursiveai.org/oneimage/cookbook/crop-image/
description: "Crop an image in C#: a rectangle, a centered square, or a fixed aspect ratio with a chosen focus, in upright coordinates. Runnable code with OneImage, on any OS."
version: "1.10.4"
---

# Crop an image in C#

Load the image, call `Crop(x, y, width, height)` with the rectangle to keep, and save. Coordinates start at the top-left corner. The program below crops NASA’s “Blue Marble” photograph (4579×4579, public domain) to a rectangle, and a public test photo from a phone to a centered square.

```shell
dotnet new console -o CropImage && cd CropImage
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
repo=https://raw.githubusercontent.com/recurser/exif-orientation-examples
curl -L -o phone.jpg $repo/master/Portrait_6.jpg
```

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

```csharp
using OneImage;

Image photo = Image.Load("photo.jpg");   // reads the headers only

// The 1200x800 region whose top-left corner is at (100, 80).
Image rect = photo.Crop(100, 80, 1200, 800);
rect.Save("crop.jpg");

// The largest centered square of a portrait phone photo.
Image phone = Image.Load("phone.jpg");   // 1200x1800 once upright
int side = Math.Min(phone.Width, phone.Height);
int x = (phone.Width - side) / 2, y = (phone.Height - side) / 2;
Image square = phone.Crop(x, y, side, side);
square.Save("square.jpg");

Console.WriteLine($"crop.jpg: {rect.Width}x{rect.Height}");
Console.WriteLine($"square.jpg: {square.Width}x{square.Height}");

try
{
    photo.Crop(4000, 4000, 1000, 1000);   // runs past the right and bottom edges
}
catch (ArgumentOutOfRangeException ex)
{
    Console.WriteLine(ex.Message.Split('\n')[0]);
}
```

```text
crop.jpg: 1200x800
square.jpg: 1200x1200
Crop rectangle lies outside the image. (Parameter 'rect')
```

The rectangle must lie inside the image, so clamp coordinates that come from users. Tiles outside the rectangle are never decoded. `Width` and `Height` are the upright size: `Load` applies a phone photo’s EXIF orientation first, so crop coordinates from a browser, which also shows photos upright, line up ([EXIF orientation](https://recursiveai.org/oneimage/cookbook/fix-exif-orientation/)).

## Crop to an aspect ratio and size

For banners and cards you usually want a fixed output size. `Resize` with `Fit.Cover` crops to the aspect ratio and resizes in one step, and `anchor:` chooses which part survives:

```csharp
using OneImage;

Image photo = Image.Load("photo.jpg");

// 16:9 at 1280x720: the center, the top, or the busiest area.
photo.Resize(width: 1280, height: 720, fit: Fit.Cover).Save("wide-center.jpg");
photo.Resize(width: 1280, height: 720, fit: Fit.Cover, anchor: Anchor.Top)
     .Save("wide-top.jpg");
photo.Resize(width: 1280, height: 720, fit: Fit.Cover, anchor: Anchor.Smart)
     .Save("wide-smart.jpg");

foreach (string file in new[] { "wide-center.jpg", "wide-top.jpg", "wide-smart.jpg" })
{
    ImageInfo info = Image.Identify(file);
    Console.WriteLine($"{file}: {info.Width}x{info.Height}");
}
```

```text
wide-center.jpg: 1280x720
wide-top.jpg: 1280x720
wide-smart.jpg: 1280x720
```

`Anchor.Smart` picks the area with the most detail. To remove a uniform border, such as the white margin of a scan, call `Trim()` instead of computing a rectangle.

## Limits

- **Out-of-range rectangles throw** `ArgumentOutOfRangeException` at the `Crop` call. Clamp first.
- **A crop of a JPEG is re-encoded**, so it isn’t lossless. Save as PNG to keep the cropped pixels exactly.
- **Animations:** the rectangle applies to every frame ([Resize an animated GIF](https://recursiveai.org/oneimage/cookbook/resize-animated-gif/)).

To crop a user-picked square from an upload, combine this with [Resize uploaded images in ASP.NET Core](https://recursiveai.org/oneimage/cookbook/resize-uploaded-images-aspnet-core/). Every geometry operation is in the [guide](https://recursiveai.org/oneimage/docs/guide/#operations).