lars from metallica and many others tried this approach with disasterous consequences and it didn't stop people sharing copyrighted music, it just pissed off their biggest fans when he took them to court and hurt their concert and merch sales (the upsell) for many years. i'm not here to tell you how to manage your business, but free advertizement sends people your way to upsell them.
check this book out. it's an important read for understanding the new free economy.
threatening your fans with legal action for sharing your pics (free advertisement) might not be the best approach.
either way, i understand your perspective and wish you all the best.
