uses Jpeg;
{$R test.res}
function LoadJpegRes(const ID: string): TJpegImage;
var
 RS: TResourceStream;
begin
 Result := TJpegImage.Create;
 RS := TResourceStream.Create(HInstance, ID, RT_RCDATA);
 try
  RS.Seek(0, soBeginning);
  Result.LoadFromStream(RS);
 finally
  RS.Free;
 end;
end;
procedure TForm1.Button1Click(Sender: TObject);
var
 MyJpeg: TJpegImage;
begin
 MyJpeg := LoadJpegRes('MYJPEG');
 Image1.Canvas.Draw(0, 0, MyJpeg);
end;

MYJPEG RCDATA "Test.jpg"