Trying to rope up traffic from image search is like trying to nail jello to a tree. To keep us on our toes, Google moved its image search engine from images.google.com to google.com in May 2010, then apparently moved image search from referral reports to organic reports in July 2011. (You can keep abreast of all kinds of changes like this in my SEO Google calendar.)
*Hat tip to AJ Kohn for the discovering that image search moved to organic in July last year.
So I wrote off tracking visits from image search. But then I started noticing an uptick in traffic from image search from various search engines — across different clients and industries, as you can see from these screenshots:
Note: I couldn’t find Bing in reports from any client profiles, even very large ones. So I reached out to Duane Forrester, who confirmed image search is enmeshed into organic, not referral traffic. So can’t segment it because there’s no referral path dimension in GA for organic sources. (If you didn’t understand that last sentence don’t worry about it.)