The WebP image format is commonly supported in most major browsers, and in most cases, the images can be smaller than the original JPG format file. WebP images are about 30% smaller than PNG and JPEG images at equivalent visual quality.
WordPress 6.1 introduced the WebP image generation feature. But, if you don’t want to use natively, you can easily disable it using a code snippet and the CDN at the edge, such as Cloudflare or the locally generating plugin version.
To get started to enable WebP image files to be generated at upload and to convert existing images in the sites media library from wp-admin, go to;
WP-Optimize > Images
WebP image format can be tested before images are converted so that the WebP version is smaller than the original image upload, be it PNG or JPG.
You can test WebP image size with many online image conversion tools before using WP-Optimize to convert new and existing images to the WebP image format.