\framesubtitle{\ldots en verder leeswerk}
\begin{figure}
\centering
- \includegraphics[width=.6\linewidth]{cover}%natwidth=500px,natheight=656]{cover}
- \caption{Mecklenburg, Robert. Managing projects with GNU make. ``O'Reilly Media, Inc.'', 2004.}
+ \includegraphics[width=.4\linewidth]{cover}
+ \caption{Mecklenburg, Robert. Managing projects with GNU make.
+ ``O'Reilly Media, Inc.'', 2004.}
\end{figure}
\end{frame}