Access Database

Hi.. I'm working with databases, Access databases to be exact, and I have a database in which there is an OLE Object type to store pictures. I have no problem retrieving these pictures and showing them in a picturebox, and actually I have no problem saving them to the database. The problem arises when I try to RETRIEVE the pictures that I'VE saved to the database through the application I've written. If I put an image in via access, I can retrieve no problem. If I put an image in via my windows form, and later try to retrieve it and throw it back into a picture box, I get the following error:

System.ArgumentException: Parameter is not valid.
at System.Drawing.Bitmap..ctor(Stream stream)


I suppose, since the error ONLY arrives when I try to bring in one of the pictures saved through the form that it is the method in which its being saved, but I'll post the code for both saving and retrieving.

Saving:
Byte[] byPicture;
MemoryStream ms = new MemoryStream();
picPicture.Image.Save(ms, picPicture.Image.RawFormat);
byPicture = ms.ToArray();
..........
DataRow newRow = thisConnection.adoDataSet.Tables["Categories"].NewRow();
newRow["Picture"] = byPicture;


Retrieving:
Byte[] byPicture;
MemoryStream ms = new MemoryStream();
byPicture = (Byte[])thisConnection.adoDataSet.Tables["Categories"].Rows[rowPos]["Picture"];
ms.Write(byPicture, 78, byPicture.Length - 78);
try
{

     Bitmap bm = new Bitmap(ms);
     picPicture.Image = bm;
}
catch (ArgumentException ae)
{
      string message = ae.ToString();
      MessageBox.Show(message);
}