How to Resize Image in Python: Simple Guide with Example

To resize an image in Python, use the Pillow library's Image.resize() method. First, open the image with Image.open(), then call resize() with the new size as a tuple, and finally save or use the resized image.

Syntax

The basic syntax to resize an image using Pillow is:

• Image.open(path): Opens the image file.
• image.resize((width, height)): Resizes the image to the specified width and height.
• image.save(path): Saves the resized image to a file.

python

from PIL import Image

image = Image.open('input.jpg')
resized_image = image.resize((new_width, new_height))
resized_image.save('output.jpg')

Example

This example opens an image named input.jpg, resizes it to 200 pixels wide and 100 pixels tall, and saves it as output.jpg.

python

from PIL import Image

# Open the original image
image = Image.open('input.jpg')

# Resize image to 200x100 pixels
resized_image = image.resize((200, 100))

# Save the resized image
resized_image.save('output.jpg')

print('Image resized and saved as output.jpg')

Output

Image resized and saved as output.jpg

Common Pitfalls

Common mistakes when resizing images include:

• Not maintaining the aspect ratio, which can distort the image.
• Forgetting to import the Pillow library or install it first using pip install Pillow.
• Using incorrect size tuples (must be integers).
• Not saving the resized image, so changes are lost.

To keep the aspect ratio, calculate the new height based on the original width and height.

python

from PIL import Image

# Wrong: distorts image by ignoring aspect ratio
image = Image.open('input.jpg')
resized = image.resize((300, 100))  # fixed size
resized.save('wrong_output.jpg')

# Right: maintain aspect ratio
width_percent = (300 / float(image.size[0]))
height_size = int((float(image.size[1]) * float(width_percent)))
resized_correct = image.resize((300, height_size))
resized_correct.save('correct_output.jpg')

Quick Reference

Tips for resizing images in Python:

• Use Pillow library: pip install Pillow.
• Open images with Image.open().
• Resize with resize((width, height)).
• Maintain aspect ratio to avoid distortion.
• Save resized images with save().

Key Takeaways

Use Pillow's Image.resize() method to resize images in Python.

Always maintain the aspect ratio to prevent image distortion.

Install Pillow with pip before using it.

Remember to save the resized image to keep changes.

Use integer tuples for the new size dimensions.