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Kelvin Ng
Kelvin Ng

Posted on • Updated on

Convert images to WebP with Raycast

webp converter

The Problem

I use screenshots quite often. The default screenshot format is uncompressed PNG, which can be large, especially when capturing items with an abundance of colors. Sending such multi-megabyte files over the internet becomes inconvenient. There are several workarounds:

  • Compress the PNG using apps available in the App Store
  • Compress the PNG with free CLI tools like PNGQuant
  • Change the default format to JPG using the command defaults write type jpg
  • Convert to WebP using CLI tools like cwebp

Regarding the compression approach, whether it's lossy or lossless, it does reduce a large portion of the file size for images with fewer colors, such as a capture of a text document. However, it isn't as effective on images with many colors, like a scenery photo.

The JPG approach is good for capturing screens with numerous colors, such as photos, but it might produce blurry edges on images with simple colors, like text documents.

WebP is an excellent format. Its modern algorithm offers the following benefits:

  • Superior compression rate compared to JPG and PNG
  • Supports both lossy and lossless compression
  • Works well on images, regardless of color complexity
  • Supports transparency

Currently, Apple doesn't allow WebP as the default capture format. Thus, you'll need to manually convert it using the CLI with desired options in the terminal, which is somewhat cumbersome.

The Solution

This is where Raycast comes in. With Raycast, you can create a script or plugin to use CLI tools and execute it effortlessly. No need for the terminal.

So I wrote a script offers the following features:

  • Retrieves the file paths of selected items in Finder
  • Converts the selected files to WebP
  • Allows the user to specify a compression rate, if desired
  • Provides a default compression rate if none is specified by the user
  • Offers an option for lossless compression

To install the script, download all files in my gist and put them in your Raycast script folder.

Code Logic

  • first retrieve the path of selected files in Finder using Apple Script
  • then create the bash script for file convertion


  • Optional quality argument defaults to 80
  • Initiates lossless compression when the user sets quality to 100
  • Supported image types: JPG, PNG, BMP, TIFF
  • Error handling includes
    • cwebp not found
    • No images selected
    • Errors encountered while executing the cwebp command


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Top comments (1)

johnalbort12 profile image
john nelson

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