I am writing a technical reference book and am looking for some software, preferably free, that will allow me to put a short sentence or two of small notes or tips in the sidebar. Each of these might fall under a particular category and have a specific heading such as "Note:" or "Warning:" as well as a related graphic to go with them. What are some good software options for doing this?
Also, I would need the side note to move with the paragraph it is related to if the paragraph gets moved.
To clarify, I would prefer if these category headings and images were added automatically if I were to specify the the category.
My preference would be software that works on Linux, Windows, and optionally Mac and can output to PDF.