When visitors wish you to bookmark your Web site, browsers such as Firefox and Internet Explorer will look for a small 16x16 icon that will represent your Web site. This icon will appear in the Favorites list and in the address bar.
This icon file must be in the Windows icon format (.ico) and placed in the same directory as the Web page or even at the root of the Web site. Furthermore it should be always named favicon.ico.
To create this favicon.ico from an image file,
open the icon editor by importing the source image file as an icon.
your icon resource should only contain 16x16 icon images (with different pixel formats such as 8-bit, 24-bit and why not 32-bit). You can of course let GConvert generate other 16x16 icon images for you: click here for more information.
click "Export icon file" still in the icon editor and save your icon file locally with the filename "favicon.ico".
To export the favicon.ico from an existing icon file,
open the file containing the icon in GConvert using Open a file.
select the icon you want in the Main Viewer.
click Save in the toolbar and select Icon in the format list.
set the filename to "favicon.ico" and in the options, select "Only save current selected icon image". Press OK.
You can then upload the new "favicon.ico" file from your local computer to your Web site.