How to display WriteableBitmap from database in ASP.NET

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ASP.NET

Silverlight

I'm using WriteablleBitmap in Silverlight to insert my image into database.
Converting wrtieablebitmap to byte[]:

public byte[] ImageToByteArray(WriteableBitmap bitmap)
        {
            int[] p = bitmap.Pixels;
            int len = p.Length << 2;
            byte[] result = new byte[len];
            Buffer.BlockCopy(p, 0, result, 0, len);
            return result;
        }

Then, using Silverlight WCF Service, I'm inserting it to database:

[OperationContract]
        public void DoWork(byte[] img, string user, int id, double cen)
        {
            DataClasses1DataContext db = new DataClasses1DataContext();
            produkty p = new produkty
            {
                zdjecie = img,
                userName = user,
                id_kategorii = id,
                cena = cen,
                opis = "opis"
            };
            db.produkties.InsertOnSubmit(p);
            try { db.SubmitChanges(); }
            catch (Exception e) { Console.WriteLine(e);  }
            return ;
        }

It should be corect becaouse i can find inserted data in my database.
Next, I'm using generic handler to display image from database in default.aspx in control - Image, but it isn't working.

Handler source code:

string id = ctx.Request.QueryString["id"];
string conn = ConfigurationManager.ConnectionStrings["ApplicationServices"].ConnectionString;
SqlConnection con = new SqlConnection(conn);
SqlCommand cmd = new SqlCommand("SELECT zdjecie FROM produkty WHERE id_produktu=@id", con);
cmd.CommandType = CommandType.Text;
//cmd.Parameters.Add("@id", id);
cmd.Parameters.AddWithValue("@id", id);
con.Open();
byte[] pict = (byte[])cmd.ExecuteScalar();
con.Close();
ctx.Response.ContentType = "image/bmp";
ctx.Response.OutputStream.Write(pict, 78, pict.Length - 78);

Database:
Table: produkty
id_produktu -> int
zdjecie->varbinary(max)
userName-> nvarchar(256)
id_kategorii->int
cena->float
opis->nvarchar(150)
What am I doing wrong? Does it necessary any convertion or something?
Sorry for my English.