Petición de subida de imágenes

if (Image != null)
                {
                    string urlMethod = Constants.BaseUrl + Constants.mob_sp_ECOMMERCE_SAVE_PRODUCT_PHOTO + "?comp_identifier=1&user_id=" + HttpUtility.UrlEncode(Comp_user_id) +
                     "&prod_id=" + HttpUtility.UrlEncode(prod_id) + "&name_file=" + HttpUtility.UrlEncode(filename) + "&prod_type=I&prod_cover=" + HttpUtility.UrlEncode(cover_.ToString()) +
                     "&prod_order=1&Token=" + Token;
                    var client = new RestClient(urlMethod);
                    client.Timeout = -1;
                    var request = new RestRequest(Method.POST);
                    request.AlwaysMultipartFormData = true;
                    request.AddHeader("Content-Type", "multipart/form-data");
                    var upfilebytes = File.ReadAllBytes(Image);
                    request.AddFile("imagen", upfilebytes, filename);
                    IRestResponse response = client.Execute(request);
                    if (response.IsSuccessful)
                    {
                        var data = new mob_sp_ECOMMERCE_SAVE_PRODUCT_PHOTO();
                        data = Newtonsoft.Json.JsonConvert.DeserializeObject<mob_sp_ECOMMERCE_SAVE_PRODUCT_PHOTO>(response.Content);
                        if (data.result == "OK")
                        {
                            await GetProductInfo(prod_id);
                        }
                        else
                        {
                            await Application.Current.MainPage.DisplayAlert("", "Ocurrio un error en el servidor", "Ok");
                            OnTask = false;
                            IsBusy = false;
                        }
                    }
                    else
                    {

                    }
                }