So let's take a look at a canonical subfloat code (http://en.wikibooks.org/wiki/LaTeX/Floats,_Figures_and_Captions)
\begin{figure}
\centering
\subfloat[A gull]{\label{fig:gull}\includegraphics[width=0.3\textwidth]{gull.jpg}}
\subfloat[A tiger]{\label{fig:tiger}\includegraphics[width=0.3\textwidth]{tiger.jpg}}
\subfloat[A mouse]{\label{fig:mouse}\includegraphics[width=0.3\textwidth]{mouse.jpg}}
\caption{Pictures of animals}
\label{fig:animals}
\end{figure}
\begin{figure}
\centering
\fbox{
\subfloat[A gull]{\label{fig:gull}\includegraphics[width=0.3\textwidth]{gull.jpg}}
\subfloat[A tiger]{\label{fig:tiger}\includegraphics[width=0.3\textwidth]{tiger.jpg}}
\subfloat[A mouse]{\label{fig:mouse}\includegraphics[width=0.3\textwidth]{mouse.jpg}}
}
\caption{Pictures of animals}
\label{fig:animals}
\end{figure}
\subfloat[A gull]{\label{fig:gull}\includegraphics[width=0.3\textwidth]{gull.jpg}} \\ %
\subfloat[A tiger]{\label{fig:tiger}\includegraphics[width=0.3\textwidth]{tiger.jpg}}
\subfloat[A mouse]{\label{fig:mouse}\includegraphics[width=0.3\textwidth]{mouse.jpg}}
}}
\begin{figure}
\centering
\fbox{
\minibox[c]{
\subfloat[A gull]{\label{fig:gull}\includegraphics[width=0.3\textwidth]{gull.jpg}} \\ %
\subfloat[A tiger]{\label{fig:tiger}\includegraphics[width=0.3\textwidth]{tiger.jpg}}
\subfloat[A mouse]{\label{fig:mouse}\includegraphics[width=0.3\textwidth]{mouse.jpg}}
}}
\caption{Pictures of animals}
\label{fig:animals}
\end{figure}