I want to add webp images to category thumbnail, how can we do this, it gives below error on adding webp images "File validation failed."
You can have .webp for product images in Magento with our WebP Optimized Images Extension.
With this extension there is no need for manually converting or uploading the .webp files.
Conversion is done automatically, with configurable compression supporting different conversion tools and 100% on your own server with no need to use and pay any 3rd Party Service.
Magento does not support webp images. Use online converter to convert webp image to jpeg then upload it on magento. https://ezgif.com/webp-to-jpg
In order to optimize your website images, use google page speed, it will convert your images to webp on runtime.
Have you looked into an image CDN?
Using a CDN like ImageEngine will automatically convert your images to WebP for supported devices. It will even resize your images to the end users device screen size and apply varying rates of compression based on the devices DPI.
Here's a handy guide on implementing it in Magento: https://www.scientiamobile.com/4-steps-to-adding-image-compression-to-magento/
This is a great option because you don't have to manually change your existing images.
I almost feel it is spammy, but just to mention: A free way of implementing WebP is here: https://www.yireo.com/software/magento-extensions/webp2