Find More Sizes Of That Image On Google Images
If you search for an image on Google Image Search and then mouse over the result, Google will let you find “more sizes” of that image. For example, I searched for [cow] and hovered my mouse over the first result. As you can see, there is a link to “more sizes” for that image:
When you click on it, you are taken to a special filter that only shows you that image, but in multiple sizes from multiple sources. Here is a look at that page:
As Alex Chitu said, this is a feature Bing had for some time and Google just recently added it.