I have four images aligned in one slide and I want to show one picture at a time.
I was able to show the text using the code below
\begin{frame}
\frametitle{Table of Contents}
\begin{itemize}
\item<1-> Introduction
\item<2-> Algorithm for reducing finite automata
\item<3-> Reliability models
\item<4-> Reduction steps
\item<5-> References
\item<6-> Conclusion
\end{itemize}
\end{frame}
In the same way I want to show the images.
I have aligned the images as follows
\begin{frame}
\vcenteredhbox{\includegraphics[width=5cm,height=5cm,keepaspectratio]{pc5.jpg}}
\vcenteredhbox{\includegraphics[width=5cm,height=5cm,keepaspectratio]{pc6.jpg}}
\vcenteredhbox{\includegraphics[width=5cm,height=5cm,keepaspectratio]{pc8.jpg}}
\vcenteredhbox{\includegraphics[width=5cm,height=5cm,keepaspectratio]{pc7.jpg}}
\end{frame}


\only<3>{.....}to show just on the third layer – David Carlisle Oct 21 '12 at 11:08\vcenteredhboxor add a pointer for it. – egreg Oct 21 '12 at 11:13