Batch convert images to webp format

What is webp? WebP is Google’s alternative smaller image format to that of JPEGs or PNGs.

You can batch convert image files with Python. One of the newer image formats is webp. WebP is an image format employing both lossy and lossless compression.

In theory this image format is smaller than others. You can convert images in a directory with the python script below

Start

Needs webp tools installed,

sudo apt-get install webp 

Then can convert images like this:

#!/usr/bin/python3
import glob
import os

quality = str(100)
imgs = glob.glob("img/*")
for img in imgs:
    print(img)

    cmd = ("cwebp -q " + quality + " " + img + " -o " + img[:img.index(".")-1] + ".webp")

    print(cmd)
    os.system(cmd)

Python function

Lets tweak that a little. Turn the whole thing in a function, so you can call it like:

webp("img/*.png",80)

Then the function:

#!/usr/bin/python3
import glob
import os

def webp(directory, quality):
    imgs = glob.glob("img/*")
    for img in imgs:
        print(img)

        cmd = ("cwebp -q " + str(quality) + " " + img + " -o " + img[:img.index(".")-1] + ".webp")
        print(cmd)
        os.system(cmd)

This will convert all the images to webp with 80% quality. When reducing quality the image files will get smaller. You'd think webp is always smaller than png, but that's not the case.

More on webp and python:

• https://www.keycdn.com/support/webp-support
• https://en.wikipedia.org/wiki/WebP
• https://pythonbasics.org/
• https://pythonprogramminglanguage.com/