I'm poking around in Mavericks and found cool new functionality in Quicklook. If you're using Quicklook to view an image, by default it will show you the entire image. If the image is larger than will fit on your screen, it will show you a scaled version.
But, in Mavericks, if you press the Option key after Quicklook has opened, the larger images will zoom in to display at the full resolution of the image.
