Just upgraded to Drupal 7.0 from 7.0-rc2, and noticed that the image uploader no longer works correctly in IE8 (it does work in Chrome and Firefox). Tried a fresh install of 7.0-rc2 and 7.0 with administrative user on both to make sure, and the issue persists. In IE8, after clicking upload, the file isn't displayed like normally, though upon saving the node, it does show that it uploaded. However, when you edit the node, you can't remove the image. Not sure what changed.