Sometimes, mozilla autorecognize favicons and show them.
I'll give some more info for the more curious, if you don't mind LoStRe:
- Favicon.ico or Favicon.gif,png ?
.ico : This is the standard format of this little icon which appears in the address bar.It's supported from all famous and known browsers and a user should not have any problem with it.If you need to insert such an icon, then you need to write a code in the <head> tags:
<link rel="Shortcut Icon" href="/path/to/favicon.ico" />
.png : New programs, like photoshop, can use and edit images better in png format.That's how some users put their icon in png format.There's a little problem here.If you need to put this like .png, IE(The regural Internet Explorer) won't detect it sometimes.Other known browsers (ex. Mozilla Firefox ) will recognize it with no problem.
BOTH : If you need to insert the png but have a backup ico file for the IE users, then you need to enter an if condition in your html code:
<link href="/path/to/favicon.ico" rel="icon"/>
<![if ! IE]>
<link href="/path/to/favicon.png" rel="shortcut icon"/>
<![endif]>
You're done!
Cheers,
-Blane