As all major browsers now supports WebP images, and file size of WebP files are substantially smaller than especially .PNG files, it’s really time to start serve WebP images if you aren’t doing that already. Luckily, there are many tools available to automate that process. One of my favourites are WebP Express, a highly configurable, robust and flexible tool, that allows you to convert to WebP images locally, without having to sign up with any third-party service.
Extract from WordPress.org
More than 4 out of 5 mobile users are using a browser that is able to display webp images. Yet, on most websites, they are served jpeg images, which are typically double the size of webp images for a given quality. What a waste of bandwidth! This plugin was created to help remedy that situation. With little effort, WordPress admins can have their site serving autogenerated webp images to browsers that supports it, while still serving jpeg and png files to browsers that does not support webp.https://wordpress.org/plugins/webp-express