arieng - 11:32 pm on Apr 17, 2013 (gmt 0)
Of course i can't find the article now, but my understanding was that the huge decline was attributable to the fact that the old interface pre-loaded the page within Google Images. That meant GA code getting triggered as a pageview even though the user hadn't clicked through to the site. The new interface doesn't do that. So while many users are seeing huge declines in their analytics reports, the actual click-throughs to the site could still be higher.
No evidence to back this up myself yet, but working on it.