TextformatterWebpImages by Ryan Cramer

Convert JPG/PNG img tags to use WEBP, auto-creating WEBP images as needed.

ProcessWire Textformatter module for WEBP Images

This module looks for references to JPG or PNG images in any formatted values you've selected it for and updates them to be WEBP images. This is intended primarily for sites that are using images in CKEditor textarea fields, as it updates any <img> tags pointing to JPG/PNG images on-the-fly, automatically creating the WEBP images when they don't exist. Because it does this as a Textformatter process, it applies to any existing pages automatically.


  • This module requires ProcessWire 3.0.132 or newer since WEBP support was added by that version of ProcessWire. It was developed with 3.0.137, so using that version or newer would be even better.

  • Your server must support WEBP either with GD or IMagick. See here for more details.

  • I also recommend that you have fallback code in your .htaccess file so that clients that do not support WEBP will automatically fallback to the JPG/PNG version (details further below).

Before installation

Unless you are already using ProcessWire webp features on your site, I recommend adding the following to your /site/config.php file. This tells ProcessWire how you want it to generate and handle webp images. Adjust as needed, but for this module I recommend keeping the useSrcExt option set to true, though it is not required.

$config->webpOptions = [
  // Quality setting of 1-100 where higher is better but bigger
  'quality' => 80,

  // Use source file extension in webp filename? (file.jpg.webp rather than file.webp)
  'useSrcExt' => true,

  // Fallback to source file URL when webp file is larger than source?
  'useSrcUrlOnSize' => true,

  // Fallback to source file URL when webp file fails for some reason?
  'useSrcUrlOnFail' => true,


  1. Copy the files for this module (or just the .module file) into new directory: /site/modules/TextformatterWebpImages/

  2. In your ProcessWire admin, click Modules > Refresh, and you'll see this module on the Site tab of your modules. Click the install button.

  3. In Setup > Fields, locate any Textarea fields where you want to automatically convert images to WEBP. This would typically be your CKEditor fields, like “body”. Edit those fields, click the “Details” tab, and select “Convert JPG/PNG images to WEBP” as one of the Text Formatters. Save.

  4. View a page that has one of the fields you just updated on it, and also has images that would be converted to WEBP. Make sure everything is working as you expect. Note That the first time (only) viewing such a page may slow down the page render since it has to generate the WEBP image

.htaccess fallback to JPG/PNG

The following .htaccess rules are useful if not all clients to the website support WEBP, enabling the original JPG/PNG files to be delivered when that is the case. This can go after the RewriteEngine On line in your .htacess file.

Option 1 (recommended)

This option requires $config->webpOptions('useSrcExt', true); in your /site/config.php file (or see the “Before installation” section above). This makes PW generate .webp files that include the original extension like filename.jpg.webp. This keeps our .htaccess rules nice and simple:

RewriteCond %{HTTP_ACCEPT} !image/webp [OR]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_URI} ^(.*)\.webp$
RewriteRule ^(.*)\.webp$ $1 [R=307,L]

Note: if running your site from a subdirectory, you likely will have to set the RewriteBase in your .htaccess file. See the RewriteBase examples already present in your .htaccess file. You'll want something like RewriteBase /your-subdir/.

Option 2

This option is what you'd want to use if not using the useSrcExt option in your $config->webpOptions. For this case we have to use a separate group of rules for each supported file extension (jpg, jpeg, png).

# fallback to JPG file when WEBP not supported or does not exist
RewriteCond %{HTTP_ACCEPT} !image/webp [OR]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{DOCUMENT_ROOT}/$1$2$3/$4.jpg -f
RewriteRule ^(.*?)(site/assets/files/)([0-9]+)/(.*)\.webp(.*)$ /$1$2$3/$4.jpg [R=307,L]

# fallback to JPEG file when WEBP not supported or does not exist
RewriteCond %{HTTP_ACCEPT} !image/webp [OR]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{DOCUMENT_ROOT}/$1$2$3/$4.jpeg -f
RewriteRule ^(.*?)(site/assets/files/)([0-9]+)/(.*)\.webp(.*)$ /$1$2$3/$4.jpeg [R=307,L]

# fallback to PNG file when WEBP not supported or does not exist
RewriteCond %{HTTP_ACCEPT} !image/webp [OR]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{DOCUMENT_ROOT}/$1$2$3/$4.png -f
RewriteRule ^(.*?)(site/assets/files/)([0-9]+)/(.*)\.webp(.*)$ /$1$2$3/$4.png [R=307,L]

Note that if you are using $config->pagefileExtendedPaths = true; in your /site/config.php file, the above rewrite rules do not support that, though it should be possible with minor adjustments.

Install and use modules at your own risk. Always have a site and database backup before installing new modules.

Latest news

  • ProcessWire Weekly #511
    In the 511th issue of ProcessWire Weekly we'll cover the latest core updates, introduce a new third party module called Auto AVIF, and more. Read on!
    Weekly.pw / 25 February 2024
  • Using date range fields in ProcessWire
    This week we'll take a detailed look at the newest addition to the ProFields set of modules: the Date Range Fieldtype and Inputfield.
    Blog / 24 November 2023
  • Subscribe to weekly ProcessWire news

I just love the easy and intuitive ProcessWire API. ProcessWire rocks!” —Jens Martsch, Web developer