WebP
WebP is an image format developed by Google and released on September 30, 2010. According to Google, it can make images 25-34% smaller.
Why isn't WebP used more often?
With WebP being a new image format, it has taken time for the major browsers and image editors to develop support for it. Due to the initial lack of support, most developers were hesitant to use the format. However, according to the Can I Use website, WebP now has a 96.3% usability rating as of January 2023. With support available in all major browsers and most image editors, WebP should be used more frequently going forward.
How to convert images into WebP
Google has made a conversion tool called cwebp, available for Linux, macOS, and Windows, that encodes JPEG (Joint Photographic Experts Group), PNG (portable network graphics), or TIFF (tagged image file format) images to WebP. Another utility called gif2webp can convert GIF (graphics interchange format) images to WebP. Additionally, a utility called dwebp can decode WebP images to PNG images. See Google's precompiled utilities page for further information and download links for each utility.
Latest versions of most image editors, including Adobe Photoshop, now support WebP.