With the launch of the new iPad all websites instantly became pixelated and ugly. All your neat images and sprites and stuff is now rubbish. You’ll need to remake it all. In twice the width and height.
When it comes to graphic and icon design it can sometimes feel like a part-time job just to keep them updated and you easily end up with billions of files scattered around in silly folders. Add retina to that, and you’ll double that number.
A retina display has twice the pixels as a normal display but at the same resolution. That means that all fixed size graphics needs to be doubled in width and height in order to keep the sharpness of the graphic.