uses
  Jpeg, ClipBrd;


procedure TfrmMain.ConvertBMP2JPEG;
var
  jpgImg: TJPEGImage;
begin
  chrtOutputSingle.CopyToClipboardBitmap;
  Image1.Picture.Bitmap.LoadFromClipboardFormat(cf_BitMap,
    ClipBoard.GetAsHandle(cf_Bitmap), 0);
  jpgImg := TJPEGImage.Create;
  jpgImg.Assign(Image1.Picture.Bitmap);
  jpgImg.SaveToFile('TChartExample.jpg');
end;