.cs

static async Task<byte[]> BlurImage(string imagePath)
{
  return await Task.Run(() =>
  {
    var image = Image.Load(imagePath);
    image.Mutate(ctx => ctx.GaussianBlur());
    using (var memoryStream = new MemoryStream())
    {
      image.SaveAsJpeg(memoryStream);
      return memoryStream.ToArray();
    }
  });
}