To: anyone finding that image-based CSS rollovers ‘blink’ in Internet Explorer, traditional or Pixy method:
Tools > Internet Options > General > Temporary Internet Files > Settings
Move the radio button from ‘Every visit to the page’ to ‘Automatically’. Remember? You turned that on to clear up IE’s caching problems? Most users don’t, so you and a handful of other developers are the only one experiencing the blink. Rejoice.
From: someone who was in the same boat until a particularly frustrating evening of testing many moons ago.