I'm trying this, but I get a little distance.
\documentclass{article}
\usepackage{graphicx}
\usepackage[a3paper,landscape]{geometry}
\begin{document}
\includegraphics[width=5cm, height=5cm]{1.png}\includegraphics[width=5cm, height=5cm]{1.png}\includegraphics[width=5cm, height=5cm]{1.png}\includegraphics[width=5cm, height=5cm]{1.png}
\includegraphics[width=5cm, height=5cm]{1.png}\includegraphics[width=5cm, height=5cm]{1.png}\includegraphics[width=5cm, height=5cm]{1.png}\includegraphics[width=5cm, height=5cm]{1.png}
\includegraphics[width=5cm, height=5cm]{1.png}\includegraphics[width=5cm, height=5cm]{1.png}\includegraphics[width=5cm, height=5cm]{1.png}\includegraphics[width=5cm, height=5cm]{1.png}
\includegraphics[width=5cm, height=5cm]{1.png}\includegraphics[width=5cm, height=5cm]{1.png}\includegraphics[width=5cm, height=5cm]{1.png}\includegraphics[width=5cm, height=5cm]{1.png}
\end{document}