Why is a favicon important
A favicon is a small image file that should live in the root directory of your web site. It provides the image that is used in:
- the browser tab
- browser bookmarks
- homescreen icons
The file can be a .ico, .gif or .png image.
It is important to have a favicon for several reasons.
Firstly, to display the branding of your website - if you omit a favicon you'll get a default blank space where you could have your logo image.
Secondly, for performance. Every time a web browser requests a page on your web site, it will also look for the favicon file. If the file is not present, the web server will return a 404 Not Found HTTP code, and your browser will not be able to show the file. This takes additional resources of the web server for zero gain, so it's a wasted effort.
Favicon files are cached by the web browser, so they are not downloaded on every page request, only on the first visit to your site.