Why does browser show smaller favicon?

In our client's website, favicon.开发者_如何学Pythonico file has several sizes from 8x8 to 32x32. I expect the 16x16 to show in browser tab, but instead it shows 8x8 icon in white frame. Why does this happen and what workarounds are there?

Favicon should be 16x16 or 32x32 at 8-bit or 24-bit, according to http://en.wikipedia.org/wiki/Favicon#Standardization_and_implementation

But in my experience, try to get the favicon to have file size 1.12KB like Google, StackOverflow etc :P

try clearing cache and rebooting. See here

Your favicon is 24 X 24, try making it 32 X 32.