add these hooks to your theme's 'functions.php' to customize Wordpress login page

wordpress-custom-login.php

function myLoginLogo() {
    ?>
    <style type="text/css">
    .login h1 a {
		height: 82px;
		background-size: auto;
		background-image: url('<?=get_template_directory_uri();?>/img/logo-login.png');
	}
    </style>
    <?php
}
add_action('login_enqueue_scripts', 'myLoginLogo');

function myLoginLogoUrl() {
    return site_url();
}
add_filter( 'login_headerurl', 'myLoginLogoUrl' );

function myLoginLogoTitle() {
    return get_bloginfo();
}
add_filter( 'login_headertitle', 'myLoginLogoTitle' );