Resize .Webp Image

Question

I had converted Jpg to Webp but i unable to Resize Webp Images

var webpFileName = file.FileId + ".webp";
using (Bitmap bitmap = new Bitmap(jpgFileName))
{
using (var saveImageStream = System.IO.File.Open(webpFileName, FileMode.Create))
{
var encoder = new SimpleEncoder();
encoder.Encode(bitmap, saveImageStream, 20);
}
}