The larger images may show up in the search results, when Google thinks an image should be highlighted. For example, the before and after:
Google also announced a new regional tag that will show up in certain situations in the Google search results. The region tags tell the searcher that the site is from a specific country or region. This region tag will only show on about 1% of the search results, Google said. And they have to meet these criteria:
We currently show region tags only for certain domains such as .com and .net where the location information would otherwise be unclear. We don't show region tags for results on domains like .br for Brazil, because the location is already implied by the green URL line in our default display. In addition, we only display region tags when the region supplied by the site owner is different from the domain where the search was entered.
Here is a picture: