Possible images 

Hi Patrick, take a look here: http://broadsides.law.harvard.edu/home.php
There are at least three broadsides with rewards:
http://pds.lib.harvard.edu/pds/view/4788306
http://pds.lib.harvard.edu/pds/view/4788237
http://pds.lib.harvard.edu/pds/view/4788336
As you can read here http://broadsides.law.harvard.edu/faq.php#post_image there is no copyright, just remember to insert the link to the exact page.