Code for How to Compress Images in Python Tutorial

compress_image.py

import os
from PIL import Image


def get_size_format(b, factor=1024, suffix="B"):
    """
    Scale bytes to its proper byte format
    e.g:
        1253656 => '1.20MB'
        1253656678 => '1.17GB'
    """
    for unit in ["", "K", "M", "G", "T", "P", "E", "Z"]:
        if b < factor:
            return f"{b:.2f}{unit}{suffix}"
        b /= factor
    return f"{b:.2f}Y{suffix}"
    


def compress_img(image_name, new_size_ratio=0.9, quality=90, width=None, height=None, to_jpg=True):
    # load the image to memory
    img = Image.open(image_name)
    # print the original image shape
    print("[*] Image shape:", img.size)
    # get the original image size in bytes
    image_size = os.path.getsize(image_name)
    # print the size before compression/resizing
    print("[*] Size before compression:", get_size_format(image_size))
    if new_size_ratio < 1.0:
        # if resizing ratio is below 1.0, then multiply width & height with this ratio to reduce image size
        img = img.resize((int(img.size[0] * new_size_ratio), int(img.size[1] * new_size_ratio)), Image.LANCZOS)
        # print new image shape
        print("[+] New Image shape:", img.size)
    elif width and height:
        # if width and height are set, resize with them instead
        img = img.resize((width, height), Image.LANCZOS)
        # print new image shape
        print("[+] New Image shape:", img.size)
    # split the filename and extension
    filename, ext = os.path.splitext(image_name)
    # make new filename appending _compressed to the original file name
    if to_jpg:
        # change the extension to JPEG
        new_filename = f"{filename}_compressed.jpg"
    else:
        # retain the same extension of the original image
        new_filename = f"{filename}_compressed{ext}"
    try:
        # save the image with the corresponding quality and optimize set to True
        img.save(new_filename, quality=quality, optimize=True)
    except OSError:
        # convert the image to RGB mode first
        img = img.convert("RGB")
        # save the image with the corresponding quality and optimize set to True
        img.save(new_filename, quality=quality, optimize=True)
    print("[+] New file saved:", new_filename)
    # get the new image size in bytes
    new_image_size = os.path.getsize(new_filename)
    # print the new size in a good format
    print("[+] Size after compression:", get_size_format(new_image_size))
    # calculate the saving bytes
    saving_diff = new_image_size - image_size
    # print the saving percentage
    print(f"[+] Image size change: {saving_diff/image_size*100:.2f}% of the original image size.")
    
    
if __name__ == "__main__":
    import argparse
    parser = argparse.ArgumentParser(description="Simple Python script for compressing and resizing images")
    parser.add_argument("image", help="Target image to compress and/or resize")
    parser.add_argument("-j", "--to-jpg", action="store_true", help="Whether to convert the image to the JPEG format")
    parser.add_argument("-q", "--quality", type=int, help="Quality ranging from a minimum of 0 (worst) to a maximum of 95 (best). Default is 90", default=90)
    parser.add_argument("-r", "--resize-ratio", type=float, help="Resizing ratio from 0 to 1, setting to 0.5 will multiply width & height of the image by 0.5. Default is 1.0", default=1.0)
    parser.add_argument("-w", "--width", type=int, help="The new width image, make sure to set it with the `height` parameter")
    parser.add_argument("-hh", "--height", type=int, help="The new height for the image, make sure to set it with the `width` parameter")
    args = parser.parse_args()
    # print the passed arguments
    print("="*50)
    print("[*] Image:", args.image)
    print("[*] To JPEG:", args.to_jpg)
    print("[*] Quality:", args.quality)
    print("[*] Resizing ratio:", args.resize_ratio)
    if args.width and args.height:
        print("[*] Width:", args.width)
        print("[*] Height:", args.height)
    print("="*50)
    # compress the image
    compress_img(args.image, args.resize_ratio, args.quality, args.width, args.height, args.to_jpg)