Vous devrez faire quelques ajustements mineurs, mais comme début....
\documentclass{beamer}
\usetheme{IMT}
\title{Title}
\subtitle{Subtitle}
\author{names}
\begin{document}
\IMTtitlepage
\IMTtableofcontents
\section{title}
\subsection{title}
\begin{frame}
\frametitle{frametitle}
\framesubtitle{subtitle}
content
\begin{itemize}
\item test
\end{itemize}
\end{frame}
\end{document}
![alt text][1]
Avec:
`beamerthemeIMT.sty`
\setbeamertemplate{navigation symbols}{}
\setbeamercolor{title}{fg=white}
\setbeamercolor{subtitle}{fg=white}
\setbeamerfont{title}{size=\Large,series=\bfseries}
\setbeamerfont{subtitle}{size=\Large,series=\mdseries}
\setbeamercolor{structure}{fg=orange}
\setbeamerfont{frametitle}{series=\bfseries,size=\large}
\setbeamerfont{section in toc}{series=\bfseries}
\setbeamerfont{subsection in toc}{size=\footnotesize}
\setbeamercolor{section page}{fg=white}
\setbeamerfont{section page}{size=\Large,series=\bfseries}
\setbeamercolor{frametitle}{fg=black}
\setbeamercolor{title in head/foot}{fg=gray}
\setbeamertemplate{section in toc}[sections numbered]
\setbeamertemplate{subsection in toc}[subsections numbered]
\setbeamertemplate{background canvas}{\includegraphics[width=\paperwidth]{slide}}
\newcommand{\IMTtitlepage}{
\begingroup
\setbeamertemplate{background canvas}{\includegraphics[width=\paperwidth]{title}}
\begin{frame}[plain,c]
\hfill
\begin{minipage}{.5\textwidth}
\flushright%
{%
\usebeamerfont{title}%
\usebeamercolor[fg]{title}%
\ifx\inserttitle\empty\else\inserttitle\par\fi
}%
{%
\usebeamerfont{subtitle}%
\usebeamercolor[fg]{title}%
\ifx\insertsubtitle\empty\else\insertsubtitle\par\fi
}
\end{minipage}
\end{frame}
\endgroup
}
\newcommand{\IMTtableofcontents}{
\begingroup
\setbeamertemplate{background canvas}{\includegraphics[width=\paperwidth]{toc}}
\begin{frame}[plain,t]
\vspace*{1cm}
\begin{columns}[onlytextwidth,t]
\begin{column}{.6\textwidth}
\usebeamerfont{frametitle}%
\color{white}%
Sommaire
\end{column}
\begin{column}{.4\textwidth}
\tableofcontents
\end{column}
\end{columns}
\end{frame}
\endgroup
}
\AtBeginSection{%
\begingroup
\setbeamertemplate{background canvas}{\includegraphics[width=\paperwidth]{section}}
\begin{frame}[plain,c]
\hfill
\begin{minipage}{.5\textwidth}
\flushright%
{%
\usebeamerfont{section page}%
\usebeamercolor[fg]{section page}%
\insertsection\par
}%
\end{minipage}
\end{frame}
\endgroup
}
\setbeamertemplate{frametitle}{%
\ifbeamercolorempty[bg]{frametitle}{}{\nointerlineskip}%
\hskip-0.3cm%
\begin{beamercolorbox}[sep=0.3cm,wd=.8\textwidth]{frametitle}
\usebeamerfont{frametitle}%
\vbox{}\vskip-1ex%
\strut\insertframetitle\strut\par%
{%
\ifx\insertframesubtitle\@empty%
\else%
{\usebeamerfont{framesubtitle}\usebeamercolor[fg]{framesubtitle}\strut\insertframesubtitle\strut\par}%
\fi
}%
\vskip-1ex%
\end{beamercolorbox}%
\hfill
\begin{beamercolorbox}[sep=0.3cm,wd=.2\textwidth]{frametitle}
\usebeamerfont{frametitle}%
\vbox{}
\strut\hfill\structure{\insertframenumber}\strut\par%
\end{beamercolorbox}%
}
\setbeamertemplate{footline}{%
\leavevmode%
\hbox{%
\begin{beamercolorbox}[wd=.2\paperwidth,ht=2.25ex,dp=1ex,center]{author in head/foot}%
\end{beamercolorbox}%
\begin{beamercolorbox}[wd=.6\paperwidth,ht=2.25ex,dp=1ex,center]{title in head/foot}%
\usebeamerfont{title in head/foot}\insertshorttitle
\end{beamercolorbox}%
\begin{beamercolorbox}[wd=.2\paperwidth,ht=2.25ex,dp=1ex,right]{date in head/foot}%
\end{beamercolorbox}}%
\vskip10pt%
}
`slide.png`
<img src="/upfiles/slide.png" style="width: 50%;"/>
`title.png`
<img src="/upfiles/title.png" style="width: 50%;"/>
`toc.png`
<img src="/upfiles/toc.png" style="width: 50%;"/>
`section.png`
<img src="/upfiles/section.png" style="width: 50%;"/>
---
[1]: https://texnique.fr/osqa/upfiles/Screen_Shot_2020-10-01_at_16.07.23.png
[2]: https://texnique.fr/osqa/upfiles/slide.png
[3]: https://texnique.fr/osqa/upfiles/title.png
[4]: https://texnique.fr/osqa/upfiles/toc.png
[5]: https://texnique.fr/osqa/upfiles/section.pnghttps://texnique.fr/osqa/upfiles/section.png