[stream]

Could someone explain why the author suggests 4 sizes in the favicon.ico including 24x24 and 64x64? Why not use an ICO with only 16x16 and 32x32 image formats? Thanks in advance.

[bbrks]

And because favicons are now being used in many other places, such as Safari’s Reader and IE9’s pinned sites, the best approach is to supply a higher resolution favicon, at least 64x64 pixels.

[stream]

Damn I totally missed that, thank you very much. The Reading List in Safari may use 64x64 for the Retina display.

[heptat]

Microsoft suggests 24x24: http://msdn.microsoft.com/en-us/library/cc849094(VS.85).aspx...

[cremno]

This site is about IE8. This one is about IE9 on Win7: http://msdn.microsoft.com/en-us/library/ie/gg491740%28v=vs.8...

The optimal sizes are the same as the author's but 24x24 px. is missing in the recommended size list.

The site links to a blog entry about Pinned Sites in Win8. You can re-use the 144x144 px. PNG for a pinned site.