The first approach for specifying a favicon is to use the rel attribute value "icon" and to define what the value means via a profile;
In this HTML 4.01 example, the favicon identified via the URI http://example.com/myicon.png as being a favicon:
<!DOCTYPE html
PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html lang="en-US">
<head profile="http://www.w3.org/2005/10/profile">
<link rel="icon"
type="image/png"
href="http://example.com/myicon.png">
[…]
</head>
[…]
</html>
