Displaying bmp and jpg in a same TImage

Hello, I use following code to display a bitmap in a timage:

    Bmp:=TBitmap.Create;
    TBLOBField(dbMembres_Foto.FieldByName('FOTO')).SaveToStream(aStream);
    aStream.Position:=0;
    Bmp.LoadFromStream(aStream);
    dbBitmap1.Picture.Graphic:=Bmp;
    dbBitmap1.Visible:=True;

And I use similar code to do this with a jpeg:

    Jpg:=TJpegImage.Create;
    TBLOBField(dbMembres_Foto.FieldByName('FOTO')).SaveToStream(aStream);
    aStream.Position:=0;
    Jpg.LoadFromStream(aStream);
    dbBitmap1.Picture.Graphic:=Jpg;
    dbBitmap1.Visible:=True;

*** BUT: when I run the program, I get the error : "JPEG Error #052"   when
I want to use a .bmp ???? Why is that?

Below you see the complete code-chunk for this, where it runs one of the
above depending on the BLOB-type....

I would appreciate it a lot if someone could give me an answer on this...

  aStream:=TMemoryStream.Create;
  aExtention:=FieldByNAme('Formaat').AsString;
  if (aExtention='bmp') then
   begin
    Bmp:=TBitmap.Create;
    TBLOBField(dbMembres_Foto.FieldByName('FOTO')).SaveToStream(aStream);
    aStream.Position:=0;
    Bmp.LoadFromStream(aStream);
    dbBitmap1.Picture.Graphic:=Bmp;
    dbBitmap1.Visible:=True;
   end
  else
   begin
    Jpg:=TJpegImage.Create;
    TBLOBField(dbMembres_Foto.FieldByName('FOTO')).SaveToStream(aStream);
    aStream.Position:=0;
    Jpg.LoadFromStream(aStream);
    dbBitmap1.Picture.Graphic:=Jpg;
    dbBitmap1.Visible:=True;
   end;
 aStream.Free;