WebP Extension

Upon file upload this extension creates a WebP (and Avif if active) version of the uploaded image and its thumbs.

Requires a working job queue, Extension:PictureHtmlSupport, and a usable version of imagick, libwebp (cwebp), or gd installed.
As well as $wgHashedUploadDirectory = true;, and if Extension:AWS is active $wgAWSRepoHashLevels to be >0;

Setting $wgGenerateThumbnailOnParse = false; is currently not supported.

How does this work?

After an upload or file transformation, a transform job is dispatched that creates a webp (and avif if active) file version of the original file.

Additionally, the PictureHtmlSupport extension exposes a hook when a thumbnail is added to the page output.
Extension:WebP utilizes this hook to add a <source> element for each active image transformer.

Converting already uploaded images

A maintenance script exists to convert already uploaded images:

php extensions/WebP/maintenance/CreateFromLocalFiles.php

# To only convert non-thumbnails run
php extensions/WebP/maintenance/CreateFromLocalFiles.php --no-thumbs

# To create thumbnails of custom sizes run
# This will create two thumbnails with size 1000px and 1250px
php extensions/WebP/maintenance/CreateFromLocalFiles.php --thumb-sizes=1000,1250

# To only work on some images run
php extensions/WebP/maintenance/CreateFromLocalFiles.php --titles=ImageA.jpg,ImageB.png

# To force the creation of already existing images run
php extensions/WebP/maintenance/CreateFromLocalFiles.php --overwrite

# Only work on page titles matching a prefix
# Every page starting with prefix 'Example' will be selected
php extensions/WebP/maintenance/CreateFromLocalFiles.php --title-prefix=Example

# Only work on page titles matching a file-type
# Every page starting with file-type 'png' will be selected
# Can be combined with 'title-prefix'
php extensions/WebP/maintenance/CreateFromLocalFiles.php --file-type=png

Installation

wfLoadExtension( 'WebP' );

Configuration

Key	Description	Example	Default
$wgWebPEnableConvertOnUpload	Enables file creation after a new image was uploaded. Doesn't work for copy uploads.	true	true
$wgWebPEnableConvertOnTransform	Enables file creation after a thumbnail was created. This isn't necessary if a thumbhandler is active.	false	true
$wgWebPEnableResponsiveVersionJobs	Dispatch transform jobs for 1.5x and 2x file versions. Note: This runs for each thumbnail inclusion and may be disabled after all present thumbnails have been converted.	false	true
$wgWebPCheckAcceptHeader	Check if the accept header contains webp. If not the original file will be served.	true	false
$wgWebPCompressionQuality	Compression Quality. Lower means worse.	50	75
$wgWebPCompressionQualityAvif	Compression Quality for Avif files. Lower means worse.	50	30
$wgWebPFilterStrength	Alpha compression strength. Sets imagick `webp:alpha-quality` and `cwebp -alpha_q`. Lossless is 100.	50	80
$wgWebPAutoFilter	Enables the auto filter. This algorithm will spend additional time optimizing the filtering strength to reach a well-balanced quality.	false	true
$wgWebPThumbSizes	Thumbnail Sizes to create through the maintenance script	[2400]	[120, 320, 800, 1200, 1600]
$wgEnabledTransformers	List of enabled image transformers	[ "MediaWiki\Extension\WebP\Transformer\AvifTransformer", "MediaWiki\Extension\WebP\Transformer\WebPTransformer" ]	WebP Transformer
$wgWebPCWebPLocation	Path to `cwebp` executable		/usr/bin/cwebp
$wgWebPAvifencLocation	Path to `avifenc` executable		/usr/bin/avifenc

Enabling Avif

For full feature support you'll need to install Imagick v7, als v6.9 has multiple bugs.
Alternatively you can install libavif-bin (>= 0.9.3) which provides avifenc. Do note that this still requires a version of imagick installed, as avifenc can't rescale images.

When enabling the Avif transformer, make sure that it is ordered before the webp transformer, as else the browser will pick the webp version.

$wgEnabledTransformers = [ "MediaWiki\\Extension\\WebP\\Transformer\\AvifTransformer", "MediaWiki\\Extension\\WebP\\Transformer\\WebPTransformer" ];

De-Installation

Delete the folders images/webp and images/thumbs/webp and remove the extension.
If the Avif transformer is active remove images/avif and images/thumbs/avif.