Resize images in user guide pdf?

[bmcrae]

We can easily create narrower margins with pandoc (e.g. use command:

pandoc -V geometry:margin=1in --smart -o circuitscape_4_0.pdf t1.tex

but I'm not sure how to preserve the image sizes. It would be nice to do this, since we get lots of page breaks as currently implemented. I suppose we could redo images and add white space on either side if needed.