Google updated the mobile interface for Image Search launched in October. I've only noticed the change in Chrome and Safari for iPhone, but it doesn't seem to be an experiment.
Google now shows a three-dot menu with options like "visit page", "view image", "send feedback" and "search by image", instead of using links. You can still swipe to go to the next or previous image result and tapping the image sends you to the most relevant page that includes it.