Sumatra PDF adds support for WebP images. Till now you can able to view Webp images natively in Windows through Windows Photos Viewer, but for that you need to install codec provided by Google. FYI, you can still see WebP images in Chrome and Opera by dragging and dropping them, now an Windows app that supports WebP image format has joined the list and its not a browser, it’s a PDF reader- Sumatra PDF now displays WebP images also, drag and drop them onto program window.
Sumatra PDF 2.4 has added the support for Google WebP image format, you can download it from its homepage.
Want some WebP images for testing?, you can find them in Chrome Web Store Google using WebP image for extensions.