This functionality is now available without a module: https://docs.silverstripe.org/en/5/changelogs/5.3.0/#file-converter
Adds a .Webp()
function to templates to allow converting images to webp.
This is a module version of this proof of concept by Maxime Rainville.
To use this, your image driver (typically GD or Imagick) must be compiled with support for webp.
{$Image.Webp.ScaleWidth(150)}
or
{$Image.ScaleWidth(150).Webp}