\documentclass{handout}
\geometry{margin=0.5cm, left=0.5cm, right=0.5cm}
\usepackage{tabulary}
\begin{document}
\thispagestyle{empty}

\begin{center}
\begin{tabulary}{\textwidth}{C C}
\includegraphics[keepaspectratio, height=0.48\textheight]{Copyrighted/Fokus9WdhFunktionen.png} &
\includegraphics[keepaspectratio, height=0.48\textheight]{Copyrighted/Fokus9WdhFunktionen.png} \\
\includegraphics[keepaspectratio, height=0.48\textheight]{Copyrighted/Fokus9WdhFunktionen.png} &
\includegraphics[keepaspectratio, height=0.48\textheight]{Copyrighted/Fokus9WdhFunktionen.png} \\
\end{tabulary}
\end{center}

\end{document}