Is there a way to load a hidden image into a pdf output document that will show up when the user moves the cursor over a relevant piece of text?
E.g., a pdf file generated by tex contains
this arbitrary block of text
and when you move your cursor over it, a picture appears near the cursor.
You can use fancytooltips; this requires Acrobat Reader to work. A little example:
Create a file image.tex like this:
\documentclass{article}
\usepackage{graphicx}
\usepackage[createtips]{fancytooltips}
\begin{document}
\keytip{a}{\includegraphics[height=4cm]{example-image-a}}
\clearpage
\end{document}
process this file to get a file image.pdf. In the same folder, create another file (the "main" file), like this:
\documentclass{article}
\usepackage{xcolor}
\usepackage{graphicx}
\usepackage[filename=image,mouseover,noextratext,movetips]{fancytooltips}
\usepackage{lipsum}% just to generate text for the example
\begin{document}
\lipsum[4]
\tooltip{this is the designated text}{a}
\lipsum[4]
\end{document}
The string used for filename has to be the same as the name of the pdf file containing the tooltip. Process this document; when you hover over this is the designated text the image will appear in a tooltip.
An image of the resulting PDF file with the cursor away from the designated text:
and an image once the cursor hovers over the text:
