\begin{frame}
    \frametitle{Metadaten im WWW}
    \begin{center} 
        \includegraphics<1>[width=0.7\textwidth]{../../img/lightbeam_1.png}
        \includegraphics<2>[width=0.7\textwidth]{../../img/lightbeam_2.png}
    \end{center}
\end{frame}