Improve some setting descriptions in the graphics options.

More than a few of these have annoyed me for a while, what with their typos and odd wording and occasional lack of important details.

Criticisms welcome. I mean, as long as it doesn't devolve into MORE bikeshedding. Even I don't enjoy that.
Can you make tense consistent in the second sentence (i.e. change it to "A high resolution greatly improves visual quality)?