Technically, no. Each SITE has a single favicon.
Some browsers will assume the favicon is in the root directory of the site. Period.
Some browsers will allow you to point to a different favicon, and sometimes it is successful.
You can add a piece of code to your web pages but even with the code, many times the SITE favicon will show.
The REAL code for favicon to main directory is below:
<link rel="icon" href="favicon.ico" type="image/x-icon">
<link rel="shortcut icon" href="favicon.ico" type="image/x-icon">
<link REL="SHORTCUT ICON" HREF="http://www.yoursitehere.com/favicon.ico">
The MODIFIED code for favison is below: (not recommended)
<link rel="icon" href="favicon.ico" type="image/x-icon">
<link rel="shortcut icon" href="favicon.ico" type="image/x-icon">
<link REL="SHORTCUT ICON" HREF="http://www.yoursitehere.com/yoursubdirectory/favicon.ico">
The firefox icons that are wider?
Could you show me an example?
Are you referring to the GREEN area for SSL?
Firefox, by default has a large icon setting in Firefox. You can adjust this.
I make ALL my favicons at 32x32 pixels.