Ruby, Rails, Firefox, Anime, Mac
In: Web development10 Mar 2007
I also learnt from validating my favicons that you can actually place more than 1 version of the favicon image into the .ico file (it seems to be a container for these images rather than being an image itself).
Oh, and the same site also has a very handy Favicon generator – I used this to fix some of my favicons, which used to be GIFs renamed with the .ico file extension. Very handy.