how to convert latex to picture

Usually, the LaTeX is used to create documents and for these purposes you should setup MikTeX or another TeX system. If you want to create only the formula, then you should consider the type of problem to be solved. For sites with dynamic content, it is advisable to use a modules like MathJs, jsMath or online servises that provide the conversion (see http://www.codecogs.com/latex/eqneditor.php[^]).

In applications, the generation of formulas is rarely necessary.To display the formulas used images. If you need a good quality pictures use vector images. And if you create a control to display graphs, it is advisable to look for a ready-made solution from the Internet. By the way, to generate formulas the mimetex is not so huge.

You could also use MathML, there is a library that can render it: http://nugeneqml.codeplex.com/[^]. And you can use this one to convert from latex to MathML: http://latex2mathml.codeplex.com/[^].

Notice nobody LaTeX does not overwrite its just execute. Use MathML is not always a good way out of this situation. Although in some situations, you could use it, for example when programming applications for browser or Microsoft Office or if you use MFC project with HTML Dialogs.