Retrieving jpeg images from Access 97

Read this,

HOWTO: Displaying Images Stored in a BLOB Field
http://support.microsoft.com/support/kb/articles/Q173/3/08.ASP

Sorry this is a bit long but its the microsoft method of inserting a BMP image:

HOWTO: Retrieving Bitmap from Access and Displaying In Web Page
Last reviewed: July 31, 1998
Article ID: Q175261
 


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The information in this article applies to:
Microsoft Visual InterDev, version 1.0
Microsoft Active Server Pages, version 1.0b
Microsoft Visual Basic Professional and Enterprise Editions for Windows, version 5.0


SUMMARY
This article shows by example how to extract the bitmap photos in the Microsoft Access 97 Northwind.mdb database, and view them from a Web browser using Active Server Pages (ASP). In order to accomplish this task, an ActiveX DLL must be created that strips the Access and OLE headers from the field. This article shows how to create this ActiveX DLL, and how to implement it.
 

This article demonstrates how to use Visual Basic to retrieve a bitmap stored in an OLE Object field. Because the definition of OLE object storage is not documented, the following code searches the object's OLE header for characters consistent with the start of the graphic. This method may not work in all circumstances.

Be aware that Internet Explorer 3.0 is unable to display true color bitmaps. For this reason, the bitmaps stored in the Access database should be no higher than 256 colors.



Step-by-Step Example to Extract the Photos

Create a new project in Visual Basic and make the project an ActiveX DLL.

Add a reference to ActiveX Data Objects (ADO) by clicking the Project menu and selecting References. Select "Microsoft OLE DB ActiveX Data Objects 1.0 Library" and click OK.

Add a new module to the project by selecting the Project menu and clicking Add Module. Select Module and click Open.

Place the following code in the (general) (declarations) section of MODULE1.BAS:


      ' Enter the following Declare statement as one single line:
      Public Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory"
       (lpvDest As Any, lpvSource As Any, ByVal cbCopy As Long)



      Type PT
        Width As Integer
        Height As Integer
      End Type

      Type OBJECTHEADER
        Signature As Integer
        HeaderSize As Integer
        ObjectType As Long
        NameLen As Integer
        ClassLen As Integer
        NameOffset As Integer
        ClassOFfset As Integer
        ObjectSize As PT
        OleInfo As String * 256
      End Type



Place the following code in the (general) (declarations) section of CLASS1.CLS:

        Function DisplayBitmap(ByVal OleField As Variant)
        Dim Arr() As Byte
        Dim ObjHeader As OBJECTHEADER
        Dim Buffer As String
        Dim ObjectOffset As Long
        Dim BitmapOffset As Long
        Dim BitmapHeaderOffset As Integer
        Dim ArrBmp() As Byte
        Dim i As Long

        'Resize the array, then fill it with
        'the entire contents of the field
        ReDim Arr(OleField.ActualSize)
        Arr() = OleField.GetChunk(OleField.ActualSize)

        'Copy the first 19 bytes into a variable
        'of the OBJECTHEADER user defined type.
        CopyMemory ObjHeader, Arr(0), 19

        'Determine where the Access Header ends.
        ObjectOffset = ObjHeader.HeaderSize + 1

        'Grab enough bytes after the OLE header to get the bitmap header.
        Buffer = ""
        For i = ObjectOffset To ObjectOffset + 512
            Buffer = Buffer & Chr(Arr(i))
        Next i

        'Make sure the class of the object is a Paint Brush object
        If Mid(Buffer, 12, 6) = "PBrush" Then
            BitmapHeaderOffset = InStr(Buffer, "BM")
            If BitmapHeaderOffset > 0 Then

                'Calculate the beginning of the bitmap
                BitmapOffset = ObjectOffset + BitmapHeaderOffset - 1

                'Move the bitmap into its own array
                ReDim ArrBmp(UBound(Arr) - BitmapOffset)
                CopyMemory ArrBmp(0), Arr(BitmapOffset), UBound(Arr) -
                 BitmapOffset + 1

                'Return the bitmap
                DisplayBitmap = ArrBmp
            End If
        End If
      End Function



Rename the Project by selecting the Project menu, and clicking on "Project1 Properties" and type your new name in the "Project Name" field. This example assumes that you named the project "MyProject" and will refer to that name in future steps.

Make the project Apartment Model Threaded by selecting the "Unattended Execution" check box. Click OK.

Rename the Class in the Property Pane. This example assumes that you named the class "MyClass" and refers to that name in future steps.

Compile the DLL by clicking the File menu and selecting "Make MyProject.dll."

Create an ASP page named "bitmap.asp" that contains the following code:


      <%@ LANGUAGE="VBSCRIPT" %>
      <%
      '   You need to set up a System DSN named 'NWind' that points to
      '   the Northwind.mdb database
      Set DataConn = Server.CreateObject("ADODB.Connection")
      DataConn.Open "DSN=NWind", "admin", ""
      Set cmdTemp = Server.CreateObject("ADODB.Command")
      Set RS = Server.CreateObject("ADODB.Recordset")
      cmdTemp.CommandText = "SELECT Photo FROM Employees
        WHERE EmployeeID = 1"
      cmdTemp.CommandType = 1
      Set cmdTemp.ActiveConnection = DataConn
      RS.Open cmdTemp, , 0, 1
      Response.ContentType = "image/bmp"
      Set Bitmap = Server.CreateObject("MyProject.MyClass")
      Response.BinaryWrite Bitmap.DisplayBitmap(RS("Photo"))
      RS.Close
      %>



Create an HTML page named "BitmapTest.htm" that contains the following code:


      <HTML>
      <HEAD>
      <TITLE>Bitmap Test</TITLE>
      </HEAD>
      <BODY>
      <HR>
      <img src="Bitmap.asp">
      <HR>
      </BODY>
      </HTML>


 

Don`t u need SQL Server to insert a BLOB field?

Pepster,

you are right, you do need SQL server to store BLOB field...

mikeandbee,

treat Pepster's comment as an answer...

To avoid many hassles do not store the images in the database.  Only store the path to the image in one field of the database.  Then through ASP you call this field and the path to the image is inserted into the HTML.  I have also stored the dimensions of the image in separate fields and used those values to change the size of the image on the Web Page.  I can send you an example of this if you want.  E-mail me at critter017@yahoo.com

I'm not a complete expert on this, but I do know that you can insert or query Binary Large Objects(BLOB's) without SQL Server...Access97/2000 works if you have a component(dll) that handles it like www.aspsmart.com  offers...aspSmartupload..

Steve

oh...but I agree with critter017, because the fact is, when you store a gif or jpg or whatever kind of file, it's filesize may be 5kb in reality, but it quite possibly will hog over 20kb as a BLOB...this gets to be pretty inefficient...pretty fast...storing the ImagePath and calling it up as an ASP object is much simpler, and much more space efficient.

my $.02
Steve

it is easier to simply put a reference to the image in Access

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