I am hearing reports from international sources both in Germany and India about major traffic drops being noticed from the Google Image search referral.
Martin Missfeldt who watches Google Image search like a hawk covered the issue in German on his blog.
In short, when you try to access an image in Google Image search in Germany, the frame loads a white blank page, which clearly can have an impact on suspected and inferred Google referrals. Here is a picture that I was able to replicate on Google.de:
He even showed a chart that shares the pretty devastating traffic drop:
But Google USA doesn't render images like Google Germany, so the bug isn't an issue in the US.
John Mueller from Google chimed in on Martin Missfeldt's Google+ post and said "Thanks for the message, Which does not look good ...: /" (that is the translated version).
Martin also noted that Image Search seems to be indexing images way faster now.
There is a large thread about this in the Germany Webmaster Forums and Abakus Forums.
Forum discussion at Google+, Google+, Germany Webmaster Forums and Abakus Forums.
UPDATE: Google fixed the bug, around HTTPS/HTTP and it now is working again.
