# How to loop through all images (all of equal size), 2 images per page, with tikzpicture and tcolorbox on every page?

\documentclass[a4paper, landscape]{article}

\usepackage{tikz}
\usetikzlibrary{calc}

\usepackage[most]{tcolorbox}

\newcommand\UseImage[1]{%
\IfFileExists{#1.jpg}%
{\includegraphics[scale=\ImageScale]{#1.jpg}}%
{\includegraphics[scale=\ImageScale]{example-image.jpg}}%
}

% =======================================
% Input ===================================
\def\BottomTitle{Bottom Title}
\def\ImageScale{0.5}
\def\ImageLeft{\UseImage{SomeImageName-1}}
\def\ImageRight{\UseImage{SomeImageName-17}}
%
\newcommand{\PictureIndexStartsAt}{1}
\newcommand{\PictureIndexEndsAt}{16}
% =======================================
% =======================================

\begin{document}

% Page Box:
\begin{tcolorbox}[]
% Images:
\begin{tcbitemize}[raster columns=2, raster force size=false]
\tcbitem[remember as=LeftRasterbox, width=9cm] \ImageLeft
\tcbitem[remember as=RightRasterbox, width=9cm] \ImageRight
\end{tcbitemize} % remeber as=<name> for later TikZ-usage
%
\tcblower
\BottomTitle
\end{tcolorbox}

\begin{tikzpicture}

% ................ Here is more code that should be on every page, at the same spot

\end{tikzpicture}

\end{document}


You can see, that, if the files exist, the left image should print SomeImageName-1.jpg and the right image should print SomeImageName-17.jpg on page 1.

In other words, we currently have:

• SomeImageName-1.jpg (page 1, left)
• SomeImageName-17.jpg (page 1, right)

There is also some more tikzpicture code which needs to be print on every page, as well as some titles (such as BottomTitle in the example) inside a tcolorbox, which also need to be print on every page, as can be understood from the MWE.

## Now the question:

How to loop this, such that we have the following:

• SomeImageName-1.jpg (page 1, left)

• SomeImageName-17.jpg (page 1, right)

• SomeImageName-2.jpg (page 2, left)

• SomeImageName-18.jpg (page 2, right)

• ...-3.jpg (p. 3 ...

• ...-19.jpg (p. 3 ...

• and so forth untill -16.jpg (p. 16 ...

• and so forth untill -32.jpg (p. 16 ...

In short:

How to have a loop, such that multiple pages can be print, each loaded with 2 images per page, as per the loop description above?

Probably something with

• \foreach \i in {\PictureIndexStartsAt,...,\PictureIndexEndsAt}{
• \def\iPlusConstant{\the\numexpr\i+16}
• LEFT: \includegraphics[width=\textwidth]{./Pictures/XYZ-\i.jpg}
• RIGHT: \includegraphics[width=\textwidth]{./Pictures/XYZ-\iPlusConstant.jpg}
• \newpage

How to piece this together into a loop which works with this MWE please?

\documentclass[]{article}

\usepackage[most]{tcolorbox}

\newcommand\UseImageLeft[1]{%
\IfFileExists{#1\i.jpg}%
{\includegraphics[scale=\ImageScale]{#1\i.jpg}}%
{\includegraphics[scale=\ImageScale]{example-image.jpg}}%
}

\newcommand\UseImageRight[1]{%
\IfFileExists{#1\iPlusConstant.jpg}%
{\includegraphics[scale=\ImageScale]{#1\iPlusConstant.jpg}}%
{\includegraphics[scale=\ImageScale]{example-image.jpg}}%
}

% Input ===================================
\def\ImageScale{0.2}
\def\ImageLeft{\UseImageLeft{Image-}}
\def\ImageRight{\UseImageRight{Image-}}
\newcommand{\PictureIndexStartsAt}{1}
\newcommand{\PictureIndexEndsAt}{16}
\def\iPlusConstant{\the\numexpr\i+16}
% =======================================

\begin{document}

\foreach \i in {\PictureIndexStartsAt,...,\PictureIndexEndsAt}{

% On any page (begin)
\begin{tcolorbox}[]
\begin{tcbitemize}[]
\tcbitem[] \ImageLeft
\tcbitem[] \ImageRight
\end{tcbitemize}
\end{tcolorbox}
% On any page (end)

\newpage
}

\end{document}