using (System.Data.SqlClient.SqlConnection con = new System.Data.SqlClient.SqlConnection(connectionString))
{
con.Open();
byte[] bt = System.IO.File.ReadAllBytes(@"D:\image.jpg");
System.Data.SqlClient.SqlCommand cmd = new System.Data.SqlClient.SqlCommand();
cmd.Connection = con;
cmd.CommandType = CommandType.StoredProcedure;
cmd.CommandText = "your_storedprocedure_name";
System.Data.SqlClient.SqlParameter param = new System.Data.SqlClient.SqlParameter("@imgdata", bt);
cmd.Parameters.Add(param);
cmd.ExecuteNonQuery();
con.Close();
}