PIL Pillow Image Processing Guide | Generated by AI
What is PIL/Pillow?
PIL originally stood for Python Imaging Library, but it’s now maintained as the Pillow package (a modern fork). You import it as PIL in code, but you need to install Pillow via pip. It’s used for opening, manipulating, and saving image files in Python. Supports formats like JPEG, PNG, GIF, BMP, and more.
Installation
To use PIL, install Pillow:
pip install pillow
Basic Import and Usage
After installing, import it like this in your Python script:
from PIL import Image
No need for import PIL.Image—this directly imports the Image module.
Common Image Operations
Here’s how to perform basic tasks. Assume you have an image file named example.jpg in your directory.
1. Opening an Image
image = Image.open('example.jpg') # Opens the image file
image.show() # Displays it (works on systems with an image viewer)
2. Getting Image Info
print(image.format) # e.g., 'JPEG'
print(image.size) # Tuple: (width, height)
print(image.mode) # e.g., 'RGB' for color images
3. Resizing an Image
resized = image.resize((800, 600)) # Resize to 800x600 pixels
resized.save('resized_example.jpg') # Save the resized image
4. Converting Formats
image.convert('L').save('grayscale_example.png') # Convert to grayscale and save as PNG
5. Rotating an Image
rotated = image.rotate(90) # Rotate 90 degrees clockwise
rotated.save('rotated_example.jpg')
6. Cropping an Image
left, top, right, bottom = 100, 100, 300, 300 # Define crop box (x1, y1, x2, y2)
cropped = image.crop((left, top, right, bottom))
cropped.save('cropped_example.jpg')
7. Applying Filters (Requires Extra Imports)
For filters, import ImageFilter:
from PIL import ImageFilter
blurred = image.filter(ImageFilter.BLUR) # Apply blur filter
blurred.save('blurred_example.jpg')
Advanced Example: Batch Processing Multiple Images
import os
from PIL import Image
# Resize all JPEG images in a folder to 200x200
input_folder = 'images/'
output_folder = 'resized_images/'
os.makedirs(output_folder, exist_ok=True)
for filename in os.listdir(input_folder):
if filename.endswith('.jpg'):
image = Image.open(os.path.join(input_folder, filename))
resized = image.resize((200, 200))
resized.save(os.path.join(output_folder, filename))
Tips and Notes
- Error Handling: Use try-except for invalid files, e.g.,
try: image = Image.open('file.jpg'). - Memory Efficiency: For large images, use
image.close()after operations to free memory. - Documentation: Check Pillow’s full docs at pillow.readthedocs.io for more functions like drawing, text addition, or EXIF data handling.
- Dependencies: Pillow might need system libraries (e.g., libjpeg) on some setups; see the installation guide if issues arise.
If you have a specific task or error, provide more details for tailored help!