[Tex/LaTex] multiple logos in titlegraphics of beamer

Question

I am using tikz to put four logos inside the titlegraphic. But I get an error saying,

! Undefined control sequence.
\tikz@invoke@collected@onpath ...mmand \tikz@temp 
                                                  \pgf@stop \tikz@node@is@a@...
l.46 \end{frame}

My code is like this (I use metropolis theme),

\documentclass[12pt]{beamer}
\usetheme{metropolis}
\mode<handout>{
  \usepackage{pgfpages}
  \pgfpagesuselayout{2 on 1}[a4paper,border shrink=5mm]
}
\usepackage{tikz}


\title{Title Page}
\author{Authors}
\date{Dates}
\titlegraphic{
\tikz[overlay] \node[at=(current page.south east), anchor=south east] { \includegraphics[width=0.25\textwidth]{hsyc} \includegraphics[width=0.25\textwidth]{MS2T} \includegraphics[width=0.25\textwidth]{Invest} \includegraphics[width=0.25\textwidth]{card} }
}

\begin{document}
\AtBeginSection[]{
  \begin{frame}<handout:0>
    \frametitle{Outline}
    \tableofcontents[current,currentsection,currentsubsection]
  \end{frame}
}

\begin{frame}
  \titlepage
\end{frame}

\end{document}

I also would like to see the outline of the presentation just after the title. How can I achieve it ?

Answer 1

Try with \begin{tikzpicture}[overlay, remember picture]:

\documentclass[12pt]{beamer}
\usetheme{metropolis}
\mode<handout>{
\usepackage{pgfpages}
\pgfpagesuselayout{2 on 1}[a4paper,border shrink=5mm]
}
\usepackage{tikz}


\title{Title Page}
\author{Authors}
\date{Dates}
\titlegraphic{
\begin{tikzpicture}[overlay, remember picture]
\node[at=(current page.south east), anchor=south east] {%
\includegraphics[width=.25\textwidth]{example-image} \includegraphics[width=.25\textwidth]{example-image} \includegraphics[width=.25\textwidth]{example-image} \includegraphics[width=.25\textwidth]{example-image} 
};
\end{tikzpicture}
}

\begin{document}
\AtBeginSection[]{
\begin{frame}<handout:0>
\frametitle{Outline}
\tableofcontents[current,currentsection,currentsubsection]
\end{frame}
}

\begin{frame}
\titlepage
\end{frame}

\end{document}