I scanned a document recently and I wanted to put all the images into a PDF as a coherent document. This may be very simple with Adobe Acrobat, but it's expensive and I didn't have it available. It turns out it's very simple with LaTeX too so this is what I did:

pdfize.tex

\documentclass{article}
\usepackage{graphicx}
\usepackage[margin=-0.01cm]{geometry}
\begin{document}
\includegraphics{image_1}
\includegraphics{image_2}
% ...
\includegraphics{image_n}
\end{document}