You may use Microsoft Paint or BandiView to convert your WebP image to an image in other formats including GIF, JPG, and PNG. BandiView is an image viewer and can convert a large number of images at the same time.
If your WebP image is an animated one, you may use Honeycam to convert the image to not only a GIF image but also a WebM and MP4 video.
You may use BandiView to convert a JPG and PNG image to a WebP image. BandiView can convert a large number of images at the same time.
You may use Honeycam to convert an animated GIF image to an animated WebP image quite easily.
Please visit the following link to learn about how to convert images with Honeycam.