tema/function.php

add_action("login_head", "my_login_head");
function my_login_head() {
	echo '
	<style>
	body.login #login h1 a {
		background: url("http://www.pools.it/wp-content/uploads/2015/12/pools-logo2.png") no-repeat scroll center top transparent;
		height: 120px;
		width: 300px;
	}
	</style>
	';
}

function loginpage_custom_link() {
	return 'http://www.pools.it';
}
add_filter('login_headerurl','loginpage_custom_link');