How to change WordPress logo on login page

If you want to change the WordPress Login screen logo to your own site logo for branding, you can change it easily. Insert below code into theme functions.php.
<?php //Change default login logo function my_custom_login_logo() { echo '<style type="text/css"> h1 a { background-image:url('.get_bloginfo('template_directory').'/images/login_logo.gif) !important; } </style>'; } add_action('login_head', 'my_custom_login_logo'); ?>
Create your logo in 274px X 63px size and name it login_logo.gif. Upload it into theme images folder. You are done.