When you view WebP Images in the Windows Photo Viewer, they
appear to be a lot darker, than intended and they look ugly.

To fix this, you need to remove the Windows WebP Extention and switch to the original Google version (Google is the WebP inventor)

In Powershell (run and type powershell, then the command below) write this
Get-AppxPackage *Microsoft.WebpImageExtension* | Remove-AppxPackage

Install the working version from from Google
https://storage.googleapis.com/downloads.webmproject.org/releases/webp/WebpCodecSetup.exe

If you don’t like this, you can either restore the Windows Version with the powershell command below, or reinstall it from Microsoft Store (also linked below)
Add-AppxPackage -register “C:\Program Files\WindowsApps\Microsoft.WebpImageExtension_1.0.32731.0_x64__8wekyb3d8bbwe\AppxManifest.xml” -DisableDevelopmentMode

Webp Image Extensions – Microsoft Store:
https://www.microsoft.com/en-us/p/webp-image-extensions/9pg2dk419drg