{
 This tip show, how to get the filesize, width, height, bitcount and color used
 from a bitmap.
 Dieses Beispiel zeigt, wie man Dateigrosse, breite, hohe, Farbtiefe und Farbanzahl
 von einem Bitmap ausliest.
}

 procedure TForm1.Button1Click(Sender: TObject);
 var
  fileheader: TBitmapfileheader;
  infoheader: TBitmapinfoheader;
  s: TFilestream;
 begin
  s := TFileStream.Create('c:\YourBitmap.bmp', fmOpenRead);
  try
  s.Read(fileheader, SizeOf(fileheader));
  s.Read(infoheader, SizeOf(infoheader));
  finally
  s.Free;
  end;
  listbox1.Items.Clear;
  listbox1.Items.Add('Filesize: ' + IntToStr(fileheader.bfSize));
  listbox1.Items.Add('Width: ' + IntToStr(infoheader.biWidth));
  listbox1.Items.Add('Height: ' + IntToStr(infoheader.biHeight));
  listbox1.Items.Add('BitCount: ' + IntToStr(infoheader.biBitCount));
  listbox1.Items.Add('Used: ' + IntToStr(infoheader.biClrUsed));
 end;
 {
 BitCount:
 1 = black/white
 4 = 16 colors
 8 = 256 colors
}