Add section on static content.

README.md

@@ -123,6 +123,20 @@ are used:
     ```  
     Note that you can omit the `.md` suffix from the filename.
 
+4.  *Static content*  
+    Hugo has special handling for static content (images, linked zip files, etc.).  In the root of the repo,
+    there is a `static/` directory; all static content should go there.  Subdirectories can be made to keep
+    things organized; there are existing directories for `images` and `attachments`.  Feel free to create
+    additional directories if it makes sense.  To link to static content, you can use an absolute path from
+    any page.  For example, assuming there is an image in the repo at `static/images/my_image.png`,
+    you can link to it using the `figure` shortcode as `{{< figure src="/images/my_image.png" >}}`.
+    -  **Special note for .png files**:  In order to keep the repo size as small as possible, all images
+       should be png's if possible, and further processed using the [pngquant](https://pngquant.org) compression
+       tool.  This will reduce the size by ~3-4x while keeping good quality.  For example, to process and
+       overwrite all png files in a directory, run `pngquant --ext .png --force *.png`.  *Do the processing
+       prior to committing the files to the repo, otherwise git will be forced to keep multiple copies as the files
+       are binary.*
+
 #### Adding your changes
 
 Once you've got your set of changes, add and commit them to your branch.  Push the branch and