As a sibling comment tersely stated, I have to think that such a shift to image searches will be dominated by pornography. Remember that porn accounts for an enormous fraction of web traffic and searches.

A friend once quipped, "the best porn site in the world is Google." As "reverse image searches" (where you provide an image for the service to find image matches, similar photos, associated information on the photo to figure out the identity of the person in the photo) improve in quality and data mining from the pages they find the related images from, the more people will shift their behavior to this from the current text based searching.

There will of course be searches for similar looking wardrobe or other commerce or travel reasons. But online porn is a behemoth that will overshadow any other image based search motive. It is driven by one of man's three basic desires after all (nourishment, sleep, and sex).