Add signature png on Line

Question

I have the following question. I have the following sample code. I have my signature (sig.png) in an image file. How do I have to adapt the code so that this image file is automatically placed on the stroke? Preferably dynamically adaptable to the text length

\documentclass[11pt]{article}
\usepackage{csquotes}
\usepackage{lipsum}
\begin{document}
    \pagestyle{plain}
    \begin{minipage}{0.45\linewidth}
    \end{minipage}
    \begin{minipage}{0.55\linewidth}
       \flushright
    \end{minipage}
    \lipsum[3-5]\vspace{12mm}
    \begin{minipage}{0.50\linewidth}
       M"unchen, den \today
    \end{minipage}
    \begin{minipage}[t]{0.50\linewidth}
       \begin{center}
          \rule{\linewidth}{0.5pt}\
          \newpage
          Unterschrift
       \end{center}
    \end{minipage}
    \newpage
\end{document}

Help is much appreciated!