Apple is upgrading some of the images on its website to support the high-resolution new iPad that will ship soon. The update is bringing images that are clearer, specifically for users surfing Apple.com using the new iPad. The resolution of these new images is roughly double that of the originals. AppleInsider reports that only the homepage and the iPad portion of the site have been upgraded with new high-resolution images so far.
It appears that image updates have been going slow because on some pages not all images are updated. Images that haven't been updated appear blurry on the high-resolution screen. The high-resolution graphics will also support HiDPI on OS X Lion, which was enabled with the 10.7.3 release.
A source tells AppleInsider that when in HiDPI mode Safari loads normal resolution versions first and then renders the double resolution versions. That makes images look pixilated to begin with and then resolved into a clear image as the download continues. Apple is also said to be using a 2x tag to differentiate normal and high-resolution versions of the same image.