Balíček JPEG prináša niekoľko hotových tried pre prácu s JPEG obrázkami.

uses JPEG;
 
//Quality: 1-100, 1 - nizka, 100 - vysoka
Procedure Bmp2Jpg (FileName : String; Quality : Integer);
type
  TJPEGQualityRange = 1..100;
var bmp : TBitmap;
    Jpg : TJpegImage;
begin
  bmp := TBitmap.Create;
  jpg := TJpegImage.Create;
  try
    bmp.LoadFromFile (FileName);
    Jpg.CompressionQuality := Quality;
    Jpg.Assign(bmp);
    Jpg.SaveToFile ( ChangeFileExt(FileName, '.jpg' ));
  finally
    jpg.Free;
    bmp.Free;
  end;
end;
 
procedure TForm1.Button1Click(Sender: TObject);
begin
  Bmp2Jpg('C:\pic.bmp',100);
end;