to put an icon on the browser's address bar you will need a 32x32 pictures.

the file must be with .ico extension and it must be named favicon

so for example, if you create a small image file you must name it favicon.ico

then put it on your web root directory

so when you visit your site, you will see the logo of your website within the URL in the address bar

this works on mozilla firefox and chrome

i tried internet explorer, but on older versions it does not work