Why WebP files are hard to open
WebP is Google's image format for the web: small files, optional transparency and an animated mode. Browsers save it whenever a site serves it, which is how so many downloaded pictures end up as .webp files that other programs will not open.
Pick the destination by what you need. Choose JPG for photos and maximum compatibility, accepting a white background where the image was transparent. Choose PNG when the picture has a transparent background or you want a lossless copy to edit.
What to expect
An animated WebP becomes a still image built from its first frame. Rotation tags on photos are applied so the converted picture is upright, and files are identified by their contents rather than their names.