I am guessing TikZ is going to be involved somewhere in the answer, but I may also want to put in images I created in other software into the page margins. How might I go about doing something like this in general?
pstricks looks like a great starting point: https://tex.stackexchange.com/a/29805/49339
background,tikzpagenodespackage etc. Examples: http://tex.stackexchange.com/a/103314/10898 – azetina Jan 13 '15 at 03:35