My new favicon works in Safari and Chrome, but it's weirdly split in Firefox on Mac or Windows:
However, if you navigate to the favicon itself it appears fine:
You can see how it looks in your browser here:
I created the file as a png and later a jpg in Acorn. I converted it to .ico using Graphicconverter. I've also tried converting the png to an ico in other programs.
Has anyone seen this problem before?