Bug Description

I just tried to convert a existing site to webp with performance lab + modern image.

Steps to reproduce

1. Install and enable both plugins
2. Change setting to "webp"
3. Use wp-cli to regenerate all images: wp media regenerate
4. After a few images it stops with the error

Fatal error: Paletter image not supported by webp in /usr/www/users/xxxxxx/staging-xxxxxx-com/releases/20240924131521/wp-includes/class-wp-image-editor.php on line 592

Screenshots

Additional Context

• PHP Version: 8.1
• OS: Linux
• Browser: chromium
• Plugin Version: 3.4.1 / 2.2.0
• Device: Desktop

It seems the fix is to convert the image to RGB if it isn't already: https://stackoverflow.com/questions/39292617/fatal-error-paletter-image-not-supported-by-webp