I tried searching and never really found an answer.
Is Sweetfx allowed/tolerated on Nostalrius?
It's a free 3rd party plugin that you can download for free and works with just about any game and allows you to effectively improve the games graphics by adding options like HDR/Bloom/SMAA/FXAA and so on.
For example I've used it on old classics like Kotor 1-2 and it has a massive boost to the games graphics.