In preparation for the public availability of the new iPad, Apple has quietly update their website with hi resolution graphics for an enhanced experience on the Retina Display.
If you want to view these hi-res images using Safari on your desktop computer, you can. Macotakara has discovered a method.
In Safari choose Preference then Advanced and check Show Develop menu in menu bar. Navigate to http://www.apple.com, right click on the homepage and choose Inspect Element.
Click Console, paste in the following, and hit Enter:
AC.ImageReplacer._devicePixelRatio = 2
You should now be able to zoom in (View: Zoom) to see the clarity of the new images.