MikeNoLastName - 10:19 am on Aug 15, 2013 (gmt 0)
The images traffic is a big clue. It is not at all like text SEO. WMT can show you the relative traffic between images and html I think. Look for coincident scapers of the images. We had a #1 image from the 90's that got scraped and took our place on G images search. We sent them a cease and desist notice. They removed it. It took a good 6 weeks for us to get back into the images listings at #3.