As I was reading through Searching for images with filetype: on Google? by Dan Russell of Google, I was not that surprised that filetype: takes different arguments and finds different things on Google.com and image search. I had seen this behavior. But this was stunning:
“to find an image, you have to use Images.Google.com. “
Dan’s post implied that
Google’s index for images is separate from its main index.
I emailed Dan and asked whether it was, indeed, true. Yes, he replied:
“Images, Videos, News, Web, Scholar (etc.) are all in separate indices. Normally we blend all of the results