Respond problem for upload image

I know is an old problem but I have an issue for the respond where I tried to return a response by using asp.net to return a response
below is my code(services code to save into directory and return a response):
(code in ashx asp.net)
`           context.Response.ContentType = "text/plain";
            context.Response.Expires = -1;
            try
            {
                HttpPostedFile postedFile = context.Request.Files[0] as HttpPostedFile;
                string tempPath = "/uploadImg";
                string savePath = context.Server.MapPath(tempPath);
                string filename = postedFile.FileName;
                if (!Directory.Exists(savePath))
                {
                    Directory.CreateDirectory(savePath);
                }
                string path = savePath + @"\" + filename;
                postedFile.SaveAs(path);

                Stream s = postedFile.InputStream;
                Image img = System.Drawing.Image.FromStream(s);

                int imgHeight = (int)img.PhysicalDimension.Height;
                int imgWidth = (int)img.PhysicalDimension.Width;

                TempModel tempModel = new TempModel();
                tempModel.type = "image";
                tempModel.src = "http://localhost:2002" + tempPath + "/" + filename;
                tempModel.height = imgHeight.ToString();
                tempModel.width = imgWidth.ToString();

                TempData tempData = new TempData();
                tempData.data = new List<TempModel>();
                tempData.data.Add(tempModel);


                string jsonString = JsonConvert.SerializeObject(tempData);
                string jsonRespond = jsonString.Insert(9,"\"" + "http://localhost:2002" + tempPath + "/\",");

                context.Response.Write(jsonRespond);
                context.Response.StatusCode = 200;



            }catch(Exception ex)
            {
                context.Response.Write("Error: " + ex.Message);
            }`
the code can save image to the directory but there is an error when parsing the response at grapesjs
what I facing is when i dropped my image the image couldn't automatic show in the panel.
I refered to the #138 but still having response problem