A just in time image transformation service.

cms, Craft, craftcms, Jitter, craft-plugin, craftcms-plugin, image-manipulation, lazy-loading, lazysizes


Just In Time Image Transformations

Jitter is a just in time image transformation plugin for Craft CMS. The API is based on Imgix. This plugin was created to be a simple and free alternative to an Imgix style service. It does not and will not have all the bells and whistles that other paid services/plugins offer. If you need something a bit more advanced besides basic image transformations I suggest you pay for Imgix or select a different Craft Plugin.


This plugin requires Craft CMS 3.0.0-beta.23 or later and ImageMagick.


To install the plugin, follow these instructions.

  1. Open your terminal and go to your Craft project:

     cd /path/to/project
  2. Then tell Composer to load the plugin:

     composer require codewithkyle/jitter
  3. In the Control Panel, go to Settings → Plugins and click the “Install” button for Jitter.

Configuring Jitter

Jitter can be configured by adding a jitter.php file to your projects config/ directory.


return [
    'accessKey' => getenv("S3_PUBLIC_KEY"),
    'secretAccessKey' => getenv("S3_PRIVATE_KEY"),
    'region' => 'us-east-2',
    'bucket' => 'bucket-name',
    'folder' => 'transformed-images',

Using Jitter

Requesting an image transformation through the API:


Requesting an image transformation via Twig:

{# This will transform the image on page load #}
{% set transformedImageUrl = craft.jitter.transformImage(entry.image[0], { w: 150, ar: "1:1", m: "fit", fm: "gif", q: 10 }) %}

{# For a faster template render build the API URL instead #}
{% set transformedImageUrl = "/jitter/v1/transform&id=" ~ entry.image[0].id ~ "&w=150&ar=1:1&m=fit&fm=gif&q=10" %}

    src="{{ transformedImageUrl }}" 
    srcset="{{ craft.jitter.srcset(entry.image[0], [
        { w: 300, h: 250, },
        { w: 768, ar: "16:9", },
        { w: 1024, ar: "16:9", },
    ]) }}" 

Transformation parameters:

Parameter Default Description Valid options
id null the image asset id int
path null the image asset id int
w base image width desired image width int
h base image height desired image height int
ar base image aspect ratio desired aspect ratio int:int
fm auto desired image format jpg, png, gif, auto
q 80 desired image quality 0 to 100
m clip how the image should be resized crop, clip, fit, letterbox
bg ffffff letterbox background color hex
fp-x 0.5 or asset focal point horizontal focus point 0 to 1
fp-y 0.5 or asset focal point vertical focus point 0 to 1

The auto format type will return a webp image when the server can generate the format and the client's browser supports the format.


  • Roadmap & API documentation
  • Create image transformation service
  • Create image transformation twig variable
  • Add AWS S3 bucket support
  • Add focus point parameters
  • Add srcset() functionality
  • Add cache clearing functionality
    • Delete local files
    • Delete S3 files
  • Initial release