[Still Using Air]

Yes, the image comes up. However, for dialup connections, a 256K file takes a LONG time to display. I ran this quickly thru 'Save for Web' in Photoshop, and it can be 'shrunk' to a 40K file that displays quickly on dialup, and looks the same.
I design sites, and have to take this into consideration.

[Old Airplane Driver]

That was a file that had been previously severely compressed with JPG and contained a number of artifacts. It was mainly posted just to demonstrate the capability of current browsers, not to demonstrate the compression capability of PNG. It is possible to do much better from a compression standpoint. I appreciate your concern with image size, as I maintain a couple of websites myself. I keep hoping that JPEG2000 will get more attention, as it potentially has greater compression capability than JPG and produces much higher-quality images. The neat thing about PNG is that it supports both 48 bit color and transparency. If you need transparency now, you are stuck with GIF and a 256 color palette.

In any case, the patents will soon run out and we will be free to use whatever compression technique and file format we wish.