Bulk WebP Conversion Script - Python

Python Script for Converting PNG/JPG files to WebP

During the creation of this script, I have tested multiple images with decent reductions in size and minimal quality loss. I have provided examples of quality and size at the end of this post.

Environment setup

Create a folder on your computer and name it WebPConverter or anything you desire. Within this folder we will want to create the convert.py file and a folder named bulk_images. You will want to place your PNG/JPG images within this folder.

The folder structure should look like the bellow:

WebP Conversion Script

Step 1

We will be using 2 libraries for this, Path and PIL. Path comes as standard with python but PIL will need to be installed with the below command: pip install Pillow We will then want to import both libraries:

from pathlib import Path
from PIL import Image

Step 2

Now you will need to create a convert_files function that will process the actual image conversion.

def convert_files(input):
    file_name = input.with_suffix(".webp")
    image = Image.open(input)
    image.save(file_name, format="webp")
    return file_name

This will be taking an input of the file name/location and outputting the file with the same name but in a WebP format.

Step 3

We will now make a gather_input function that will find the files in either a JPG or PNG format and push those to the convert_files function.

def gather_input():
    pngs = Path("bulk_images").glob("*.png")
    jpgs = Path("bulk_images").glob("*.jpg")

    for png in pngs:
        png_to_webp_path = convert_files(png)
        print(png_to_webp_path)

    for jpg in jpgs:
        jpg_to_webp_path = convert_files(jpg)
        print(jpg_to_webp_path)

Step 4

Now you will just want to call the latter function and the script will convert all files within the bulk_images folder.

gather_input()

After some testing, it takes roughly around 1 minute to convert 200 images, so in many cases, this can be a huge time saver.

Examples I have tested two images one PNG and one JPG and hosted them on this page to showcase the difference in size and why WebP is a much more efficient image format overall.

Image1 (JPG) = 224 kb Image1 (WebP) = 80 kb Image2 (JPG) = 64 kb Image2 (WebP) = 44 kb

Final Code

from pathlib import Path
from PIL import Image

def convert_files(input):
    file_name = input.with_suffix(".webp")
    image = Image.open(input)
    image.save(file_name, format="webp")
    return file_name

def gather_input():
    pngs = Path("bulk_images").glob("*.png")
    jpgs = Path("bulk_images").glob("*.jpg")

    for png in pngs:
        png_to_webp_path = convert_files(png)
        print(png_to_webp_path)

    for jpg in jpgs:
        jpg_to_webp_path = convert_files(jpg)
        print(jpg_to_webp_path)

gather_input()

If there are any questions regarding this script or any improvements that could be made, please don't hesitate to contact me.

Python - Bulk WebP Conversion Script