Saving Images and Binary Files to a Database with Delphi 2

In the code below are some of the magic numbers of popular file formats I found while playing around. They work fine for me but if the I missed something do let me know.

Here is the full code:

procedure TForm1.Button1Click(Sender: TObject);
var
 iPKey:integer;
 MStream:TMemoryStream;
 Sig1,Sig2:  WORD;  //16-bit unsigned integer  = 2 bytes
begin
 iPKey:=StrToInt(ediPKey.Text);
 ADODataSet1.Connection:=ADOConnection1;
 ADODataSet1.CommandText:='Select * From lmgTbl Where PKey=:param0';
 ADODataSet1.Parameters.ParamByName('param0').Value:=iPKey;
 ADODataSet1.Open;
 MStream:=TMemoryStream.Create;
 try
 TBlobField(ADODataSet1.FieldByName('Image')).SaveToStream(MStream);
    MStream.Seek(0, soFromBeginning);
    MStream.Read(Sig1,2);
    MStream.Position := 2;
    MStream.Read(Sig2,2);
    if (Sig1=$4D42) then  // little Endian format of the first 2 bytes of bitmap
     begin
       MStream.SaveToFile('Img'+IntToStr(iPKey)+'.bmp');
       ShowMessage('File saved as Bitmap');
     end
     else
      //ShowMessage('File is not Bitmap');
      if (Sig1 = $D8FF) and (Sig2 = $E0FF) then // little Endian format of the first 4 bytes of  JPEG
      begin
        MStream.SaveToFile('Img'+IntToStr(iPKey)+'.jpg');
        ShowMessage('File saved as JPEG');
      end
      else
       if (Sig1 = $4947) and (Sig2 = $3846) then // little Endian format of the first 4 bytes of GIF
        begin
        MStream.SaveToFile('Img'+IntToStr(iPKey)+'.gif');
        ShowMessage('File saved as GIF');
        end
         else
         if (Sig1 = $5025)and (Sig2 = $4644) then // // little Endian format of the first 4 bytes of PDF
         begin
        MStream.SaveToFile('Doc'+IntToStr(iPKey)+'.pdf');
        ShowMessage('File saved as PDF');
         end
         else
          if (Sig1 = $CFD0) and (Sig2 = $E011) then // // little Endian format of the first 4 bytes of DOC
        begin
        MStream.SaveToFile('Doc'+IntToStr(iPKey)+'.doc');
        ShowMessage('File saved as DOC');
        end
        else
          if (Sig1 = $4B50) and (Sig2 = $0403)  then // // little Endian format of the first 4 bytes of ZIP
        begin
        MStream.SaveToFile('Archive'+IntToStr(iPKey)+'.zip');
        ShowMessage('File saved as ZIP');
        end
         else
         begin        // unrecognized
        MStream.SaveToFile('File'+IntToStr(iPKey)+'.dat');
        ShowMessage('Unrecognized file format! '+#13+'saved with .dat extension');
        end;
     finally
  MStream.Free;
 end;
end;
end;

Danish Ahmed
Mindfire Solutions