Hi Doug,
I'm the creator of global build stats plugin, don't hesitate to ask for questions / enhancements :-)
To my mind, the capture you're referring to is using "text sections" in the list configuration, where are configured tests results image REST urls ( url like <hudson url>/job/<job name>/test/trend?width=400&height=300 )
You can, as well, refer to global build stats charts in a section like this (see the
Global build stats JSON & REST API for this : for example :
<hudson_url>/plugin/global-build-stats/showChart?buildStatId=<Chart id> )
Frédéric