Btukfyl

I am working on a book which each chapter has an image .jpg or .png. The code that accomplishes this is:

newcommand{thechapterimage}{}

newcommand{chapterimage}[1]{renewcommand{thechapterimage}{#1}}

defthechapter{arabic{chapter}}

def@makechapterhead#1{

thispagestyle{empty}

{centering normalfontsffamily

ifnum c@secnumdepth >m@ne

if@mainmatter

startcontents

begin{tikzpicture}[remember picture,overlay]

node at (current page.north west)

{begin{tikzpicture}[remember picture,overlay]



node[anchor=north west,inner sep=0pt] at (0,0) {includegraphics[width=paperwidth]{thechapterimage}};



%Comentando las 3 líneas de abajo quita la caja de contenidos en el título del capítulo

draw[rounded corners=10pt, fill=white,opacity=0.5] (1cm,0cm) rectangle (8cm,-9.3cm);                   %%%%%%%%%%%%%%%%%%% minitabla

node[anchor=north west] at (1cm,.25cm) {parbox[t][8cm][t]{6.5cm}{hugebfseriesflushleft printcontents{l}{1}{setcounter{tocdepth}{2}}}};



draw[anchor=west] (5cm,-9cm) node [rounded corners=25pt,fill=white,fill opacity=.6,text opacity=1,draw=colordominante,draw opacity=1,line width=2pt,inner sep=15pt]{hugesffamilybfseriestextcolor{black}{thechapter --- #1vphantom{plPQq}makebox[22cm]{}}};

end{tikzpicture}};

end{tikzpicture}}parvspace*{230p@}

In the main document, you would call the name of a figure just before the chapter command:

chapterimage{imagen4.png} 

chapter{Estadística y probabilidad}

Whose generated image is

The question is whether it is possible to modify the previous code where a .tex file that directly draws the image is inserted, something like chapterimage{input{pascal.tex}} this because if only one image is included it loses quality.