I have div and span elements with PNG-24 background images. The background image is pixel sharp, however, they appear blurry in IE8 despite the browser’s zoom being set at 100% and text at medium size.
Strangely, when I scroll down and back up, the background images appear sharp again.
This is how it appears:

After scrolling down and back up, this is how it appears:

Even in this case, its a bit blurry. This does not occur in IE6, IE7 or IE9.
I had the same problem – PNG-24 images look fine in Firefox but very blurry in IE8. The solution, in IE8 go to Tools > Internet Options > Advanced Tab. In the tree, under the Multimedia deselect Enable Automatic Image Resizing. This should fix the problem.