Read and Write BLOB fields using ADO.NET

ReadWriteBlob.cs

private byte[] ReadBlob(int id)
{
    byte[] result = null;

    var conn = new SqlConnection("Your connection string");
    conn.Open();
    string sql = String.Format("select Photo from MyTable where ID={0}", id);
    var cmd = conn.CreateCommand();
    cmd.CommandText = sql;
    var reader = cmd.ExecuteReader();
    if (reader.Read()) 
    {
        result = (byte[]) reader["Photo"];
    }
    return result;
}

private void WriteBlob(int id, byte[] data)
{
    var conn = new SqlConnection("Your connection string");
    conn.Open();
    string sql = String.Format("update MyTable set Photo=@Photo where ID={0}", id);
    var cmd = conn.CreateCommand();
    cmd.CommandText = sql;
    cmd.Parameters.Add("@Photo", SqlDbType.VarBinary, -1); // for VARBINARY(MAX) column.
    cmd.Parameters["@Photo"].Value = data;
    int updateCount = cmd.ExecuteNonQuery();
}