anchor.diff:              actualChart.SaveImage(ms, ImageFormat.Png)
               ms.ToArray()
   
  +        member self.ToData(?size) =
  +            let bytes = match size with Some size -> self.ToPng(size) | _ -> self.ToPng()
  +            let base64 = Convert.ToBase64String(bytes)
  +            let data = "data:image/png;base64,"+base64
  +            data
  +
       type FSharp.Charting.Chart with
       
           /// Wraps a GenericChartWithSize around the GenericChart
  
positive.code:             Data = bytes;
          }
  
      /// Loads a local image from disk and wraps a BinaryOutput around the image data.
      static member Image (fileName:string) =
          Util.Image (File.ReadAllBytes(fileName))
  
negative.code:             File.WriteAllBytes(path, content)
              "/static/temp/"+name
          with exc ->
              exc.ToString()        