Software & AppsOperating SystemLinux

How To Crop Images Using Command Line Tools Only

Ubuntu 17

In this modern age, image manipulation is a common task that we perform almost daily. While there are numerous graphical tools available to perform such tasks, sometimes you might need to automate these tasks or use a command-line interface (CLI) due to the lack of a graphical interface. This article will guide you on how to crop images using command-line tools only. We will be using a powerful tool called ImageMagick.

Quick Answer

Yes, it is possible to crop images using command line tools only. ImageMagick is a powerful tool that allows you to manipulate images directly from the command line. By using the convert or mogrify commands, you can easily crop images by specifying the dimensions and offsets. Additionally, you can use a Python script to automate more complex cropping tasks.

Introduction to ImageMagick

ImageMagick is a robust collection of tools and libraries to read, write, and manipulate an image in any of the more popular image formats. It can crop, resize, rotate, apply various effects, and do much more. In this article, we will focus on how to use ImageMagick to crop images.

Installing ImageMagick

Before we start cropping images, we need to ensure that ImageMagick is installed on our system. You can install it using the package manager of your Linux distribution. For Ubuntu, you can use the following command:

sudo apt-get install imagemagick

For other distributions or operating systems, you can refer to the official ImageMagick installation instructions.

Cropping Images Using ImageMagick

ImageMagick provides two commands for cropping images: convert and mogrify.

Using the convert command

The convert command allows you to crop an image and save it as a new file. The syntax for the command is as follows:

convert input.jpg -crop WxH+X+Y output.jpg

In this command:

  • input.jpg is the original image that you want to crop.
  • W is the width of the crop rectangle.
  • H is the height of the crop rectangle.
  • X is the horizontal offset (distance from the left edge of the image to the left edge of the crop rectangle).
  • Y is the vertical offset (distance from the top edge of the image to the top edge of the crop rectangle).
  • output.jpg is the file name of the cropped image.

For example, if you want to crop a 100×100 pixel area from the top left corner of an image, you would use the following command:

convert input.jpg -crop 100x100+0+0 output.jpg

Using the mogrify command

The mogrify command is similar to the convert command, but it modifies the original image file instead of creating a new one. The syntax for the command is as follows:

mogrify -crop WxH+X+Y input.jpg

The parameters are the same as the convert command.

Using a Python Script

For more complex tasks, you might want to use a script. Here is an example of a Python script that uses ImageMagick to crop an image:

#!/usr/bin/env python3
import subprocess
import sys

img = sys.argv[1]
left = sys.argv[2]
right = sys.argv[3]
top = sys.argv[4]
bottom = sys.argv[5]

img_base = img[:img.rfind(".")]
extension = img[img.rfind("."):]
path = img[:img.rfind("/")]
img_out = img_base + "[cropped]" + extension

data = subprocess.check_output(["identify", img]).decode("utf-8").strip().replace(img, "")
size = [int(n) for n in data.replace(img, "").split()[1].split("x")]

w = str(size[0] - int(left) - int(right))
h = str(size[1] - int(top) - int(bottom))
x = left
y = top

cmd = ["convert", img, "-crop", w + "x" + h + "+" + x + "+" + y, "+repage", img_out]

This script takes five arguments: the image file path, and the number of pixels to crop from the left, right, top, and bottom. It then calculates the size of the crop rectangle and its offset, and uses the convert command to crop the image.


ImageMagick is a powerful tool that allows you to manipulate images directly from the command line. This can be very useful for automating tasks or working on systems without a graphical interface. With the knowledge from this article, you should now be able to crop images using command-line tools only.

Can I crop images of any format using ImageMagick?

Yes, ImageMagick supports cropping images of various formats including JPEG, PNG, GIF, and more.

Can I crop multiple images at once using ImageMagick?

Yes, you can use a loop or a script to crop multiple images at once using ImageMagick. You can modify the command to include multiple input files and specify different crop parameters for each image.

Will cropping an image using ImageMagick affect the original image?

It depends on the command you use. The convert command creates a new cropped image without modifying the original image. However, the mogrify command modifies the original image file itself. Make sure to create a backup of your original image before using the mogrify command.

Can I crop images using percentages instead of pixels?

Yes, you can specify the crop dimensions and offsets using percentages instead of pixels. For example, you can use convert input.jpg -crop 50%x50%+0+0 output.jpg to crop an image to 50% of its original width and height, starting from the top left corner.

Is ImageMagick available for Windows?

Yes, ImageMagick is available for Windows. You can download the Windows installer from the official ImageMagick website and follow the installation instructions.

Can I use ImageMagick to resize an image while cropping it?

Yes, you can combine cropping and resizing in a single command using ImageMagick. You can specify the desired dimensions for both cropping and resizing, and ImageMagick will perform both operations simultaneously.

Are there any other command-line tools available for cropping images?

Yes, there are other command-line tools available for cropping images, such as GraphicsMagick and FFmpeg. However, ImageMagick is widely used and offers extensive features for image manipulation, making it a popular choice for command-line image cropping.

Leave a Comment

Your email address will not be published. Required fields are marked *