---
layout: post
title: "Batch Converting Images to webp with macOS Automator"
date: 2021-10-15
---


A great deal of my time working as a web/UI designer is spent exporting and/or converting images for software products and websites. Although a lot of modern applications can render image conversions at build time, a custom conversion is sometimes requested for an image to be set as `webp`.

You *could* download one of the many native apps from the Mac App Store to do this for you - but why not create your own script and run it with a simple right-click directly inside Finder? **Let's do just that!**

## Basic requirements

**Important!**: As of this time of writing, the official `libwebp` package release is *libwebp-1.2.1-mac-10.15*. If this has been updated since then, change the command below to match that of the proper release version.

1) First you will need to download the `libwebp` package to your Downloads folder: [developers.google.com/speed/webp/download](https://developers.google.com/speed/webp/download) 
  - *Look for the "Download for macOS link"*

2) Next we will need to copy the `cwebp` folder to our `/usr/local/bin` directory:
  - Open macOS Terminal
  - Run `sudo cp /Downloads/libwebp-1.2.1-mac-10.15/bin/cwebp /usr/local/bin`
  - *Note:* if the `/usr/local/bin` directory doesn't exist, simply create it by running: `sudo cd /usr/local && mkdir bin`

## Creating our custom Automator script

1) Open the macOS Automator from the Applications folder

2) Select `Quick Option` from the first prompt

3) Set "Workflow receives current" to `image files`

4) Set the label "in" to `Finder`

5) From the left pane, select "Library > Utilities"

6) From the presented choices in the next pane, drag and drop `Run Shell Script` into the far right pane

7) Set the area "Pass input" to `as arguments`

8) Enter the following code below as your script and type `⌘-S` to save (name it something like "Convert to webp")


	for f in "$@"
	do
	/usr/local/bin/cwebp -q 85 "$f" -o "${f%.*}.webp"
	done


For visual reference, it should look something like this:

<figure>
<img src="/public/images/automator.png" alt="macOS Automator">
<figcaption>(<a href="/public/images/automator.webp">link to hi-res image</a>)</figcaption>
</figure>

And when right-clicking an image file in the Finder window, it should now give you the option to convert:

<figure>
<img src="/public/images/automator-2.png" alt="Right click to convert">
<figcaption>(<a href="/public/images/automator-2.webp">link to hi-res image</a>)</figcaption>
</figure>

## Making edits to your script

If you ever have the need to edit this script (for example, changing the default `85` quality parameter), you will need to navigate to your `~/Library/Services` folder and open your custom webp Quick Action in the Automator application. 

Simple as that!

## Possible Hiccups

I was contacted by the very helpful [Kev Quirk](https://kevq.uk) about a minor problem he encountered while following this tutorial. When trying to run `cwebp` he received the following error message:


	cwebp cannot be opened because it's from an unverified developer


Doing the next steps seemed to have fixed this issue for him:

1. Click on the "Open in Finder" in the error message prompt
2. Double-click on the `cwebp` utility to open in Terminal
3. You'll then be prompted with a pop-up asking if you wish to execute

After following these steps, the issue should be resolved.