Chapter Cover pages with image and chapter numbering

Question

I am currently writing my thesis and would like to edit the template I am using MastersDoctoralThesis. Precisely, I would like to have every chapter being introduced with 4 pages (#1: page displaying the number of the chapter in large; #2: full page image; #3: the abstract or a quotation relating to the chapter; #4: title and number of the chapter with a short note on the authors at the bottom). Despite looking for this for a couple of days now on various platforms this seems to be rather hard to accomplish. Hence, I would be more than grateful to receive help on this as it defnitely exceeds my personal capabilities.

Please find below:

• main.tex MWE
• chapter.tex MWE
• chapter definitions from the .cls file
• Image of example chapter cover
• link to the template I use

1. main MWE

\usepackage[utf8]{inputenc} characters
\usepackage[T1]{fontenc} 
\usepackage{awesomebox}
\usepackage{lmodern} 
\usepackage{framed}
\definecolor{shadecolor}{named}{Snow2}
\usepackage{babel}  
\usepackage{csquotes} 
\usepackage[
  backend=biber,
  style=apa,
  sorting=nty,
  defernumbers=true,
  giveninits=true,
  refsection=chapter,
]{biblatex}
\addbibresource{Bibliography.bib} 
\geometry{
    paper=a4paper,
    inner=2.5cm, 
    outer=3.8cm, 
    bindingoffset=.5cm,
    top=1.5cm, 
    bottom=1.5cm, 
    showframe,}
\begin{document}
\frontmatter 
\pagestyle{plain} 
\begin{titlepage}
\begin{center}
\end{center}
\end{titlepage}
\pagestyle{thesis}
\include{Chapters/Chapter1}
\printbibliography[heading=bibintoc]
\end{document}

2. Chapter MWE:

    \chapter{Chapter1} 
\label{Chapter1} 
\newcommand{\keyword}[1]{\textbf{#1}}
\newcommand{\tabhead}[1]{\textbf{#1}}
\newcommand{\code}[1]{\texttt{#1}}
\newcommand{\file}[1]{\texttt{\bfseries#1}}
\newcommand{\option}[1]{\texttt{\itshape#1}}
\begin{multicols}{2}
\printbibliography[heading=subbibintoc]
\end{multicols}

3. Chapter definition (.cls)

    \ProvideDocumentCommand{\abovechapterskip}{}{\vspace*{20pt}}
\ProvideDocumentCommand{\chapterbelowskip}{}{\vspace*{40pt}}
\ProvideDocumentCommand{\chapterinbetweenskip}{}{\vspace*{20pt}}
\ProvideDocumentCommand{\autodot}{}{}
\ProvideDocumentCommand{\mdtChapapp}{}{}
\ProvideDocumentCommand{\chapteralign}{}{\raggedright}
\ProvideDocumentCommand{\chapterfont}{}{\Huge\bfseries}
\ProvideDocumentCommand{\chapterprefixfont}{}{\LARGE\bfseries}
\DeclareDocumentCommand{\@makechapterhead}{ m }{%
    \abovechapterskip
    {\parindent \z@ \chapteralign \normalfont
        \ifnum \c@secnumdepth >\m@ne
        \if@mainmatter
        \ifbool{chapteroneline}{%
            \chapterfont \mdtChapapp\thechapter\autodot\enspace
        }{%
            \chapterprefixfont \@chapapp\space \thechapter
            \par\nobreak
            \chapterinbetweenskip
        }%
        \fi
        \fi
        \interlinepenalty\@M%
        \chapterfont #1\par\nobreak
        \chapterbelowskip
    }
    \thispagestyle{\chapter@p@gestyle}
}
\def\@makeschapterhead#1{%
    \abovechapterskip
    {\parindent \z@ \chapteralign
        \normalfont
        \interlinepenalty\@M
        \chapterfont  #1\par\nobreak
        \chapterbelowskip
    }
    \thispagestyle{\chapter@p@gestyle}
}



\ProvideDocumentCommand{\addchap}{ s o m }{%
    \chapter*{#3}%
    \markboth{}{}%
    \IfBooleanTF{#1}{%
    }{%
        \IfNoValueTF{#2}{%
            \addchaptertocentry{#3}%
            \markboth{\MakeMarkcase{#3}}{\MakeMarkcase{#3}}%
        }{%
            \addchaptertocentry{#2}%
            \markboth{\MakeMarkcase{#2}}{\MakeMarkcase{#2}}%
        }%
    }%
}%

\ProvideDocumentCommand{\addsec}{ s o m }{%
    \section*{#3}%
    \markright{}%
    \IfBooleanTF{#1}{%
    }{%
        \IfNoValueTF{#2}{%
            \addcontentsline{toc}{section}{#3}%
            \markright{\MakeMarkcase{#3}}%%
        }{%
            \addcontentsline{toc}{section}{#2}%
            \markright{\MakeMarkcase{#2}}%
        }%
    }%
}%

4. Link to the template: https://www.latextemplates.com/template/masters-doctoral-thesis

5. Image of example chapter cover (described above)

Answer 1

This is not really an answer but I think that it is too long for a comment.

First thank you for providing lots of code but I wasn't prepared to go chasing around after your MastersDoctoralThesis template. I also didn't want to clutter up my OS with lots of ancillary files such as your chapter MWE and the chapter definition (.cls) file and merged then all into a single \documentclass{book} file and made appropriate adjustments to comment out code that that was only supported by the class you were using.

% chapter4pageprob.tex  SE 550596

\documentclass{book}
\usepackage{comment} %%%%%%%%% for my convenience
\usepackage{lipsum}  %%%%%%%%% for my convenience
\usepackage{multicol} % not in book class
\usepackage[utf8]{inputenc} % characters % why is this in the main MWE?
\usepackage[T1]{fontenc} 
\usepackage{awesomebox}
\usepackage{lmodern} 
\usepackage{framed}
% \definecolor{shadecolor}{named}{Snow2}
\usepackage{babel}  
\usepackage{csquotes} 
\usepackage[
  backend=biber,
  style=apa,
  sorting=nty,
  defernumbers=true,
  giveninits=true,
  refsection=chapter,
]{biblatex}
\addbibresource{Bibliography.bib} 
\begin{comment} % geometry macro undefined
\geometry{
    paper=a4paper,
    inner=2.5cm, 
    outer=3.8cm, 
    bindingoffset=.5cm,
    top=1.5cm, 
    bottom=1.5cm, 
    showframe,}
\end{comment}
%%%%%%%%%%%%  the .cls Chapter definition
    \ProvideDocumentCommand{\abovechapterskip}{}{\vspace*{20pt}}
\ProvideDocumentCommand{\chapterbelowskip}{}{\vspace*{40pt}}
\ProvideDocumentCommand{\chapterinbetweenskip}{}{\vspace*{20pt}}
\ProvideDocumentCommand{\autodot}{}{}
\ProvideDocumentCommand{\mdtChapapp}{}{}
\ProvideDocumentCommand{\chapteralign}{}{\raggedright}
\ProvideDocumentCommand{\chapterfont}{}{\Huge\bfseries}
\ProvideDocumentCommand{\chapterprefixfont}{}{\LARGE\bfseries}
\makeatletter     %%% this is not in a .cls file
\DeclareDocumentCommand{\@makechapterhead}{ m }{%
    \abovechapterskip
    {\parindent \z@ \chapteralign \normalfont
        \ifnum \c@secnumdepth >\m@ne
        \if@mainmatter
        \ifbool{chapteroneline}{%
            \chapterfont \mdtChapapp\thechapter\autodot\enspace
        }{%
            \chapterprefixfont \@chapapp\space \thechapter
            \par\nobreak
            \chapterinbetweenskip
        }%
        \fi
        \fi
        \interlinepenalty\@M%
        \chapterfont #1\par\nobreak
        \chapterbelowskip
    }
%    \thispagestyle{\chapter@p@gestyle}
   \thispagestyle{plain}
}
\def\@makeschapterhead#1{%
    \abovechapterskip
    {\parindent \z@ \chapteralign
        \normalfont
        \interlinepenalty\@M
        \chapterfont  #1\par\nobreak
        \chapterbelowskip
    }
%    \thispagestyle{\chapter@p@gestyle}
   \thispagestyle{plain}
}



\ProvideDocumentCommand{\addchap}{ s o m }{%
    \chapter*{#3}%
    \markboth{}{}%
    \IfBooleanTF{#1}{%
    }{%
        \IfNoValueTF{#2}{%
            \addchaptertocentry{#3}%
            \markboth{\MakeMarkcase{#3}}{\MakeMarkcase{#3}}%
        }{%
            \addchaptertocentry{#2}%
            \markboth{\MakeMarkcase{#2}}{\MakeMarkcase{#2}}%
        }%
    }%
}%

\ProvideDocumentCommand{\addsec}{ s o m }{%
    \section*{#3}%
    \markright{}%
    \IfBooleanTF{#1}{%
    }{%
        \IfNoValueTF{#2}{%
            \addcontentsline{toc}{section}{#3}%
            \markright{\MakeMarkcase{#3}}%%
        }{%
            \addcontentsline{toc}{section}{#2}%
            \markright{\MakeMarkcase{#2}}%
        }%
    }%
}%

\makeatother

%%%%%%%%%%%%
\begin{document}
\frontmatter 
\pagestyle{plain} 
\begin{titlepage}
\begin{center}
\end{center}
\end{titlepage}
% \pagestyle{thesis} % undefined in book class
% \include{Chapters/Chapter1} insert Chapter1 code here
    \chapter{Chapter1} 
\label{Chapter1} 
\newcommand{\keyword}[1]{\textbf{#1}}
\newcommand{\tabhead}[1]{\textbf{#1}}
\newcommand{\code}[1]{\texttt{#1}}
\newcommand{\file}[1]{\texttt{\bfseries#1}}
\newcommand{\option}[1]{\texttt{\itshape#1}}
\lipsum[1]
\begin{multicols}{2}
\printbibliography[heading=subbibintoc]
\end{multicols}
% above is Chapter1 code
\printbibliography[heading=bibintoc]
\end{document}

The end result was that the chapter head looks like the default. I must admit that I don't follow your \@makechapterhead code but I'm too ancient to keep up with all the new coding styles.

The \chapter macro takes two arguments \chapter[<toc entry>]{<document title>}. I think that you might be after a macro \mychapter[<toc entry>]{<document title>}{<graphic>}{<abstract>}{<authors>} where the chapter number is printed on the first page, then a \clearpage and <graphic> is printed followed by a \clearpage followed by <abstract> followed by \clearpage with a typical chapter number and title and at the bottom of the page <authors>.

Good luck.