\documentclass{beamer}
\usetheme{linutronix}
\usepackage{german}
\usepackage[utf8]{inputenc}
\usepackage{pgf}
\usepackage{graphicx}

\title{Was ist Linux?}
%% \author{Hans-Jürgen Koch}
\institute{Linutronix GmbH}

\begin{document}

\maketitle

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\begin{frame}
\begin{figure}[h]
\centering
%\includegraphics[width=8cm]{images/785px-Eniac.jpg}
\end{figure}
\end{frame}

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\begin{frame}
\begin{figure}[h]
\centering
%\includegraphics[width=8cm]{images/Thompson-sitting-Richie-standing-PDP11-1972.jpg}
\end{figure}
\end{frame}

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\begin{frame}
\begin{figure}[h]
\centering
%\includegraphics[width=5cm]{images/Apple2.jpg}
\end{figure}
\end{frame}

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\begin{frame}
\begin{figure}[h]
\centering
%\includegraphics[width=7cm]{images/800px-IBM_PC_5150.jpg}
\end{figure}
\end{frame}

% ----- Slide ------------------
\begin{frame}
\begin{figure}[h]
\centering
%\includegraphics[width=5cm]{images/CPU_und_Terminals1-600px.png}
\end{figure}
\end{frame}

\end{document}