HardOCP wrote a guide about tweaking the image quality of The Elder Scrolls V: Skyrim, you can read the article over here.
Immediately after our Skyrim gameplay performance and image quality evaluation was published, we got to work tweaking this game with built-in tools. Like many PC games, Skyrim has the ability, through INI files, to tweak various graphics settings beyond the scope of what is available through in-game graphics options.
Skyrim, like its predecessors, is based on the highly configurable Gamebryo game engine at its heart. This means there is a lot of potential tweaking that can be done by gamers and modders alike. There are also a plethora of third party utilities, not officially supported, that modders have created to improve the graphics of Skyrim. There are so many in fact, we cannot look at all of them. However, what we can do is use what the game has built-in and show you the best ways to improve the graphics, without having to download any third party utilities. We want to see what can be improved with what Skyrim has built in.