error for upload image in angularjs and webmethod.

[WebMethod]

public static string createProduct(HttpContext context, string title, string description, string spec, string price, string discount_price, string category,string sub_category, string product_uni_id, string quantity, string brand, string added_date)

{

try

{

using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["dbconnection"].ConnectionString))

{

context.Response.ContentType = "text/plain";

string dirFullPath = HttpContext.Current.Server.MapPath("~/img/products/");

string[] files;

string numFiles;

files = System.IO.Directory.GetFiles(dirFullPath);

//numFiles = files.Length;

numFiles = Convert.ToBase64String(Guid.NewGuid().ToByteArray());

string str_image = " ";

foreach (string s in context.Request.Files)

{

HttpPostedFile file = context.Request.Files[s];

string fileName = file.FileName;

string fileExtension = file.ContentType;

if(!string.IsNullOrEmpty(fileName))

{

fileExtension = Path.GetExtension(fileName);

str_image = "Product_ " + numFiles.ToString() + fileExtension;

string pathSave = HttpContext.Current.Server.MapPath("~/img/products/");

file.SaveAs(pathSave);

}

}

SqlCommand cmd = new SqlCommand("insert into tbl_products values(@title, @description, @spec, @price, @discount_price, @category, @sub_category, @images, @status, @product_uni_id, @quantity, @brand, @added_date)", con);

cmd.Parameters.AddWithValue("@title", title);

cmd.Parameters.AddWithValue("@description", description);

cmd.Parameters.AddWithValue("@spec", spec);

cmd.Parameters.AddWithValue("@price", price);

cmd.Parameters.AddWithValue("@discount_price", discount_price);

cmd.Parameters.AddWithValue("@category", category);

cmd.Parameters.AddWithValue("@sub_category", sub_category);

cmd.Parameters.AddWithValue("@images", str_image);

cmd.Parameters.AddWithValue("@status", 0);

cmd.Parameters.AddWithValue("@product_uni_id", product_uni_id);

cmd.Parameters.AddWithValue("@quantity", quantity);

cmd.Parameters.AddWithValue("@brand", brand);

cmd.Parameters.AddWithValue("@added_date", added_date);

con.Open();

cmd.ExecuteNonQuery();

con.Close();

return "0";

}

}

catch(Exception ex)

{

return ex.ToString();

}

}