A webmaster is upset that his images aren't being indexed from his site. He posted a complaint in the Google Webmaster Help forums, in which we learn two things:
(1) This webmaster was blocking Google from indexing those images with robots.txt file. This actually happens way too often.
(2) Sometimes using JavaScript for the "View Larger Image" link can make it hard for Google to index those images. Google does a pretty good job with JavaScript, but why not make it easier. Google's John Mueller said, "It seems that we're not picking up that these URLs are actually not pages but rather images -- and images without a landing page on top of that. One way to let us know about the actual connection is to use a direct link to the image (using target=_blank is fine, if you want to open them up in a new window/tab."
So if you want your images indexed, first make sure you allow Google to index them and then make sure the crawlers can process the links to them.
Forum discussion at Google Webmaster Help.
