I also lost over 70% of the traffic and adsense income overnight.
I have had varying results since this introduction.
1. My largest gallery which has had hotlink protection for a couple of years ago and serves up a 500 error when clicked on in Google, initially lost traffic but has now returned to normal however AdSense earnings are fluctuating wildly from one day to the next.
2. My second largest site has lost half of its traffic and income, period, even though this also throws a 500 error when clicked in the results or hotlinked to.
3. My third biggest's traffic is actually up by 50%, it throws the same 500 error but interestingly ALL the images are watermarked on that site.
Other sites vary but generally most have traffic down in the 50% region although overall my AdSense has not been hurt too badly since CTR is actually up with average earnings at 99.1% v January so far.
What I have noticed is, once more, a lot of scrapers using my images and blowing mine off the first page even though mine were there years before, and I mean is some cases 12 years!