How to Generate Thumbnails While Maintaining Aspect Ratio in Python

from PIL import Image

def thumbnail_with_aspect_ratio(image_path, output_path, max_width, max_height):
    with Image.open(image_path) as img:
        # Get original dimensions
        width, height = img.size

        # Calculate scaling ratio to fit within max dimensions
        ratio = min(max_width / width, max_height / height)

        # New dimensions (rounded to integers)
        new_width = int(width * ratio)
        new_height = int(height * ratio)

        # Resize using high-quality resampling
        img = img.resize((new_width, new_height), Image.Resampling.LANCZOS)

        # Save the resized image
        img.save(output_path)
        return new_width, new_height

if __name__ == "__main__":
    # Create a simple test image (400x300)
    test_img = Image.new("RGB", (400, 300), "blue")
    test_img.save("original.jpg")

    # Generate a thumbnail (max 100x100)
    result = thumbnail_with_aspect_ratio("original.jpg", "thumb.jpg", 100, 100)
    print(f"Original: 400x300 -> Thumbnail: {result[0]}x{result[1]}")