You should export as a alpha-transparency PNG-8 not PNG-24. The reason for this is that IE6 won't render any PNG-24 transparency it just makes it all opaque. Ho

You should export as a alpha-transparency PNG-8 not PNG-24. The reason for this is that IE6 won't render any PNG-24 transparency it just makes it all opaque. However with PNG-8 IE6 will make all alpha transparency transparent. This means IE6 users get a slightly chunky rounded corner and users with better browsers (IE7, FF, Safari, etc) get a smooth alpha transparency. My good friend, Nicole Sullivan, has a great presentation on this topic (http://www.slideshare.net/stubbornella/designing-fast-websites-presentation http://www.slideshare.net/stubbornella/designing-fast-websit...) see slide 55 for PNG optimization. Nicole also worked on a tool with another friend, Stoyan Stephanof, http://smush.it http://smush.it . Smush.it reduces the filesize of your images without losing quality by removing unnecessary bit data, and I think, metadata. For some of your buttons it was carving 14% off the filesize. It might be worth integrating that in for your users.