[Coda]

Because certain information in PNG files is handled differently by Macs than by Windows PCs, which could manifest as appearing as different brightnesses or being slightly faded. Your web browser on Windows completely ignores it.

I suppose it's possible that the avatar editor's backend actually DOES pay attention to it when saving the final version of the images, so what you see in the editor and what you see after you save will be different.

It's not terribly difficult to fix but it'll take a long time on the server and I don't want to start the process when there are so many users logged in.