Sorry, do you have additional information about how to change the JPEG quality in TImageEnMView?
In the following example, if JPEG quality got the value 10 or 100, the image quality and size won't change. There should be missing something, but I didn't found a hint in the manual or in the examples.
for i := 0 to TImageEnMView.MultiSelectedImagesCount - 1 do
begin
TImageEnMView.MIO.Params[i].JPEG_Quality := 80;
TImageEnMView.GetTIEBitmap(i).Write('c:\temp\test_' + IntToStr(i + 1) + '.jpg');
TImageEnMView.ReleaseBitmap(i);
end;