To change the display settings for the Flash graphs and charts under Campaign Reports, you can edit the XML template associated with the graph type. Go to admin/templates/graph/, and choose the appropriate file:
For example, if we choose the open_pie.xml file, we can change the default colors of the pie graph that shows Opened/Unopened emails on the Campaign Reports page:
Just edit the <pie> node, specifically the <colors> child:
Each color must be in it's Hex equivalent, and separated by commas. The above example indicates two shades of gray. Below is how it would appear in the Flash pie graph:
You can change any of the available settings in the XML files, and simply refresh the Campaign Reports page to view the changes.