I would like to display an image to the left of the text on a GroupBy node in my NTreeList.  (Between the +/- expander and the sub item text.)  It looks like I can display either an image or text but not both.  Is there a way to do this? 

The examples only show text and I don't see any NTreeListNode classes that offer this.  I saw the NTreeListGroupByNode but I'm not sure its helpful for this.