To change the icon that is displayed on the bookmark in a browser from the:
To something more sexy, then do the following:
Create a new folder in this location C:Program FilesCommon Filesmicrosoft sharedWeb Server Extensions15TEMPLATEIMAGES
I named mine “Custom”. This is always best practice, so that your changes wont be overwritten in any update.
Paste your new favicon file, dont forget to rename the file extension to .ico
Open your html version of the master page (if you have a custom)
Change the location inside the tag