If my invoice is matched to a PO, can I see both the PO and the invoice image?

When in the details view of an invoice, you can view both your invoice image and the PO at the same time with only a click of a button to change your view.
 
To toggle your view to show PO's along with your invoice image:
 
When in the details view of your invoice, click on the 'PO View' button on the very right side of your image tool bar.