Updated README

README.md

@@ -1,7 +1,7 @@
 # csstdg5figs [DRAFT]
 
-This repository contains the files used to create the figures for _CSS: The Definitive Guide, 5th Edition_.  I mostly did this by loading them up in Firefox OS X and using the `screenshot` command-line utility (see “[Essential Tool: Firefox’s screenshot Command](http://meyerweb.com/eric/thoughts/2015/10/22/firefoxs-screenshot-command/)” for more information)—except in the rare cases where Firefox didn’t support the thing I was illustrating, in which case I used Chrome OS X set to somewhere around 200% zoom.
+This repository contains the files used to create the figures for _CSS: The Definitive Guide, 5th Edition_.  I mostly did this by loading them up in Firefox OS X and using the `:screenshot` console utility (see “[](/)” for more information)—except in the rare cases where Firefox didn’t support the thing I was illustrating, in which case I used Chrome OS X set to somewhere around 200%–500% zoom.
 
 ## Notes
 
-* If you want an easy-to-browse method of access, load the repo-root-level `index.html` in a web browser and surf from there.  Also [available on GitHub Pages](https://meyerweb.github.io/csstdg5figs/).
+* If you want an easy-to-browse version, load the repo-root-level `index.html` in a web browser and surf from there.  NOTE: some files have to be served over HTTP in order to avoid CORS restrictions.  Also [available on GitHub Pages](https://meyerweb.github.io/csstdg5figs/).