Sometimes, Google Images results are shown in an "inline frame": when you click a picture from the results, it pops a black frame with preview, link to image, link to page and related image, as in the screenshot below:
But sometimes images in results only link to the direct image (ie clicking on an image just sends you to the image URL).
The exact same URL behaves differently on two browser, and the behavior is not consistent on the same browser, so I suspect there's a setting somewhere but I cannot find any.
Any clue?