Python Get Image Pixels Guide

Working with image pixels is a common task in Python. This guide shows how to read and manipulate image pixels using the Pillow library.

Why Get Image Pixels in Python?

Accessing image pixels lets you analyze or modify images. Common uses include image processing, computer vision, and data analysis.

For more on image processing, see our Python Image Processing Guide.

Install Pillow Library

First, install Pillow using pip:

pip install Pillow

Load an Image in Python

Use Image.open() from Pillow to load an image:

from PIL import Image

# Open an image file
img = Image.open('example.jpg')

Get Image Pixel Data

The load() method gives access to pixel data:

pixels = img.load()
width, height = img.size

# Get pixel at (x=10, y=20)
pixel_value = pixels[10, 20]
print(pixel_value)

(255, 0, 0)  # Red pixel in RGB format

Modify Image Pixels

You can change pixel values directly:

# Change pixel at (10, 20) to green
pixels[10, 20] = (0, 255, 0)

# Save modified image
img.save('modified.jpg')

Get All Pixels in an Image

Loop through all pixels to process the entire image:

for x in range(width):
    for y in range(height):
        r, g, b = pixels[x, y]
        # Process each pixel here

Convert Image to NumPy Array

For advanced processing, convert to a NumPy array:

import numpy as np

img_array = np.array(img)
print(img_array.shape)  # (height, width, channels)

For more image libraries, check our Python Image Libraries Guide.

Common Pixel Operations

Here are some common pixel operations:

# Grayscale conversion
gray_pixel = sum(pixels[x, y]) // 3

# Invert colors
inverted = tuple(255 - val for val in pixels[x, y])

Performance Considerations

Important: Pixel access can be slow for large images. For better performance:

1. Use NumPy arrays for bulk operations
2. Process smaller image sections
3. Consider parallel processing

Saving Modified Images

After modifying pixels, save the image:

img.save('output.png', format='PNG')

For saving options, see our Python Pygame Image Save Guide.

Conclusion

Getting image pixels in Python is easy with Pillow. You can read, modify, and save pixel data for various applications.

Remember to handle large images carefully for best performance. The techniques shown work for most image processing tasks.