Bitmap bmp = new Bitmap(ms) gives "Paramter used is invalid" exception

I'm trying to access jpeg image from ms access database. I m working in visual studio.net 2005. Here is my code:

string connectionString = "provider=Microsoft.Jet.OLEDB.4.0;" + @"data source=D:\\image\db.mdb";
OleDbConnection connection2 = new OleDbConnection(connectionString);
string commandString = "Select Image from img where ImageCode = 1";
OleDbCommand command2 = new OleDbCommand(commandString, connection2);
connection2.Open();
OleDbDataReader dr = command2.ExecuteReader();
dr.Read();
byte[] imgbyte = (byte[])dr["Image"];
int offset = 78;
MemoryStream ms = new MemoryStream();
ms.Write(imgbyte, offset, imgbyte.Length - offset);
Bitmap bmp = new Bitmap(ms);
bmp.Save(Response.OutputStream, ImageFormat.Jpeg);
ms.Close();
connection2.Close();

But i m getting "Parameter is invalid" error at:

Bitmap bmp = new Bitmap(ms)

Please help me to solve this..I will be higly obliged...