Peter,
Here is a small piece of code that prints an image of the graph. It uses the report tools, basically creates a new report, adds the control image (using a control reference, prits the report to the default priter and closes the report. To create the control reference just right-click in the control and select Create>>Reference. You can find this VIs in the Report palette.
Hope this helps.
Regards,
Juan Carlos
N.I.