We've gone after two individuals a few years back over copyright infringement (using our images on the front pages of their paysites) - and both times had our attorney send them a C&D letter along with a demand they pay us "compensation for potential loss of livelihood" due to the availability of our copyrighted images on their site(s).
Both of them settled (out of court) and sent us payments in the amount the lawyer had stipulated. One of them even called us at 4am EST (from Britain) after receiving the letter and shittin' in his panties.
As a side-note...you might want to check
this out about the Suze Randall vs. Max Sheridan copyright settlement (May/2000). Your current issue is comparatively minor of course, but the legal precedents it set at the time are still relevant and food-for-thought.