I would suggest to anyone who considers future action, be it legal or non-legal, to do a screenshot of  the violation of their copyright, just for evidence purposes. The courts in Germany tend to value every image copyright infringment case at 25,000 Euros. That doesn't mean 25,000 in damages for you but some legal feesof 600 to 1000 Euros - per image if they get a takedown notice from a German lawyer.

In short - there is a leverage - and it would really hurt  :D