Renumbering figure in LaTeX?

How can I make figures be renumbered in a TeX document? I want the main figures to be 1, 2, 3, ...etc. But then I want a section to have supplementary figures, S1, S2, S3, S4. The "S" does not开发者_如何学Go have to appear in the figure name, but I do want to reset the counter.

Next to reseting the counter for the figures:

\setcounter{figure}{0}

You can also add the "S" by using:

\makeatletter 
\renewcommand{\thefigure}{S\@arabic\c@figure}
\makeatother

you can reset the figure counter with

\setcounter{figure}{0}