Hello @benbyf,
You can update to the latest version of PW. If that doesn't solve the problem, convert the WebP images to a supported format like JPEG or PNG for admin use and for compressing them you can use any online application such as https://jpegcompressor.com/ it compresses JPEG, PNG and other.
Check the homepage template to check jQuery is included and also verify if there are any conflict or errors in the console that may prevent jQuery from loading.