How to display attachments image from access db in picturebox

Attachments

ImageByte = (byte[]) vcom.ExecuteScalar();

Unable to cast object of type 'System.String' to type 'System.Byte[]'.

            byte[] ImageByte = null;
            MemoryStream MemStream = null;
         
                     OleDbConnection cn = new OleDbConnection();
                     cn.ConnectionString = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=D:/ALL/Database7.accdb";

            cn.Open();
            OleDbCommand command = new OleDbCommand();
            command.Connection = cn;
            string sql = "select Attachments from Contacts where ID = 1";
        OleDbCommand vcom = new OleDbCommand(sql, cn);

ImageByte = (byte[]) vcom.ExecuteScalar();
    MemStream = new MemoryStream(ImageByte);
    pictureBox1.Image = Image.FromStream(MemStream);

            cn.Close();