Optimizing images for web

from PIL import Image
import os

def optimize_image(input_path, output_path=None, quality=85, max_width=None, max_height=None):
    """
    Compress and optionally resize an image without visible quality loss.
    - JPEG: uses quality and optimization.
    - PNG: uses optimization and no quality parameter.
    """
    if output_path is None:
        output_path = input_path  # overwrite by default

    with Image.open(input_path) as img:
        # Resize if max dimensions are set
        if max_width or max_height:
            img.thumbnail((max_width or img.width, max_height or img.height))

        # Get format (JPEG, PNG, etc.)
        img_format = img.format

        # Convert PNGs with transparency to RGB to avoid issues
        if img_format == "PNG" and img.mode in ("RGBA", "LA"):
            img = img.convert("RGBA")

        save_params = {
            "optimize": True
        }

        if img_format == "JPEG":
            save_params["quality"] = quality
            save_params["progressive"] = True

        img.save(output_path, format=img_format, **save_params)

optimize_image("input.png", "output-optimized.png", quality=50, max_width=480)