This seems to be limited to iPhones and iPads running iOS 7, so it's probably a bug. A lot of people complain about this in the Google Search Forum.
There are many reasons why the new interface is strange: loading the associated page uses more bandwidth and that's not a good idea for mobile devices, it's more difficult to check multiple search results, thumbnails are smaller and even the desktop interface shows a bigger image instead of sending users to a new page.