1. Variante
\documentclass[a4paper, 12pt]{article}
\usepackage[ngerman]{babel}
\usepackage[ansinew]{inputenc}
\usepackage{graphics}
\usepackage{graphicx}
        \begin{figure} [htc]
		\begin{center}
		   \includegraphics[width=0.5\linewidth]{5.png}
		    \caption{Grundaufbau eines Geigenbogens}
		\end{center}
	\end{figure}
2. Variante:
\usepackage{graphicx}
\makeatletter
\def\ScaleIfNeeded{
\ifdim\Gin@nat@width>\linewidth
\linewidth
\else
\Gin@nat@width
\fi
}
\makeatother
%...
\begin{document}
%...
\includegraphics[width=\ScaleIfNeeded]{Bild}
\includegraphics[width=5cm] {Bild}
Bin langsam echt verzweifelt
Lg Anna

