The WebP format can do what most of the conventional formats can do. It has support for both lossy compression used by JPG and lossless compression used by PNG, and can give animation to an image as GIF does.
Google, the developer of WebP, has released the full source code of WebP, which means that anyone can freely create, use, and distribute WebP images.
You may feel strange and unfamiliar with the WebP format, but most of us are being exposed to many WebP images frequently in our daily lives.
Video previews of YouTube displayed when you hover a mouse cursor over a video's thumbnail are WebP images. You may right-click any video's thumbnail and then click "Save image as..." to check if they really are. If your web browser is not compatible with the WebP format, however, YouTube automatically detects it and displays previews compatible with the browser instead.
Besides that, thumbnails of Netflix are also made in the WebP format.