\documentclass{article}
\usepackage[paperwidth=8.5in, paperheight=1000in, margin=0in]{geometry}
\usepackage{graphicx}
\usepackage{lmodern}
\usepackage{pgffor}
\usepackage{nopageno} % No page numbers

\begin{document}
\pagestyle{empty}

\foreach \i in {0,...,39} {
    \includegraphics[width=\paperwidth]{Guide/chunk_\ifnum\i<10 00\else\ifnum\i<100 0\fi\fi\i.png}
}

\end{document}
