Favicons are out of control. Try to look up the correct favicon stack and see how many answers you get. The standard is that there is no standard. Once you do finally decide on a compromise for what your favicon stack, you still have the manual image resizing, formatting, saving, and naming to do! In a word. Annoying.
Thankfully there is hope! realfavicongenerator.net, a site I recently ran across does all of this for you and more. Not only will it generate the favicon HTML stack for you, it will take your image and convert it to the requried sizes, formats, and naming conventions needed to create this massive stack of favicon garbage. The site also provides compression options, platform specific icons and cache-busting favicon URLs.
Next time you need to add a favicon to your site, save yourself the migrane and jump to realfavicongenerator.net instead.
P.S. you can also run it as a Gulp Plugin