Hello there,

Webp image is not supported in Helix yet. The developer team is working on it.

-Regards

In JED there are several free plugins that automatically convert all images to the Webp, while keeping the source file formats for iOS. Using only WEBP is not recommended, because of iOS began to support it since autumn 2020. If you use only a Webp, then in older iPhones it will not work. Therefore, there is no great point in supporting the Webp in SP Page Builder, if it does not save the original format with definition of devices for display.

And by the way, I personally did not notice any advantage of the WebP in front of standard formats. Webp has a larger size than the correctly compressed JPG or PNG. And has a longer loading time with the same size with existing formats. Webp is just Google's PR

Thanks Pavel for the information.