I was wondering about a possible scenario which could result from someone remote-linking to images on your web server. When you do a Google Image search and click on an image, you're taken to the page which that image appears on. Is it possible that Google could find a page remote-linking to an image and mistakenly associate the remote-linking page with the image in image search?
For instance - I could put up a page with a graphic of an elephant on it. Someone else decides they like it and remote links to it on their web page. Googlebot spots their page first, and associates the image with their page in the index. Then when Joe User does an image search for elephant and clicks on that image, they get taken to the remote linker's site instead of mine.
It happens all the time in my affiliate sites, images which are stored on the merchant site are displayed on the affiliate site. When an image search is carried out, google shows the affiliate page not the merchant page.