The "best" solution for quality is to use a full LaTeX installation, and then generate images via command line with e.g. mathTeX.
From my answer to a similar (but not duplicate, imho) question here at Super User:
MathTeX, licensed under the gpl, is a cgi program that lets you easily embed LaTeX math in your own html pages, blogs, wikis, etc. It parses a LaTeX math expression and immediately emits the corresponding gif (or png) image, rather than the usual TeX dvi. So just place an html tag in your document wherever you want to see the corresponding LaTeX expression.
It can either be used as a CGI script on the server and linked directly from the <img> tag, or run on the command-line to generate standalone image files. From the homepage:
mathTeX is usually run by your web server as a cgi program, obtaining its input expression from the query-string of an html tag. But you can also run mathTeX from your Unix shell, supplying all input on the command line. For example,
./mathtex.cgi "x^2+y^2" –o equation1 renders an image of x^2+y^2 in file
There is actually a related project called mimeTeX that sounds more or less exactly like what you want, even though the quality is said to not be as good as with a full LaTeX installation solution as mathTeX uses, and it can naturally not handle all LaTeX cases without a LaTeX installation.
Like mathTeX, it is made primarily with webservers in mind, but in the same way, it can be run from the command line. You don't specify OS, which often indicates Windows, and compilation instructions for Windows are available on the project page linked earlier.
EDIT: I noted that the mimeTeX page provides pre-compiled binaries for Windows as well, under §5.1. Just download that and follow the instructions, as any regular Windows program. If you are on e.g. Debian or Ubuntu, both mimeTeX and mathTeX are part of the main repository.