procedure TForm1.Timer1Timer(Sender: TObject);
var
bmp: TBitmap;
DC: HDC;
Jpg: TJpegImage;
Begin
Try
bmp:= TBitmap.Create;
Jpg:= TJpegImage.Create;
bmp.Height:=Screen.Height;
bmp.Width:=Screen.Width;
DC:=GetDC(0);
bitblt(bmp.Canvas.Handle, 0, 0, Screen.Width, Screen.Height,
DC, 0, 0, SRCCOPY);
Jpg.Assign(Bmp);
Jpg.SaveToFile('test.jpg');
image1.Picture.Assign(Jpg);
ReleaseDC(0, DC);
finally
Bmp.Free;
jpg.Free;
form1.Image1.Picture:=nil;  не знаю куда ее поставить????
End;
end;