It seems custom designed logo of login form gets cropped or truncated if you updated your WordPress installation to 3.8 or later.
Just for background & history of WordPress login form Logo was something like rectangular in shape as shown below:
My custom design of my Studio’s logo was right fit & was working fine as shown below:
But when WordPress updated their codebase to version 3.8 it had look of round or circular jewel, As shown below:
& that created panic in WordPress community as all custom logos got cropped or truncated by circular mask which was something looking like this:
But I later found the fix for this by just updating custom login logo code in functions.php to this:
function mas_custom_login_logo() { echo '<style type="text/css"> #login h1 a { background-image:url('.get_bloginfo('stylesheet_directory').'/images/wp-mas-logo.png) !important; background-size: 300px 75px !important; height: 75px !important; width: 300px !important; } </style>'; } add_action('login_head', 'mas_custom_login_logo');
Note: change width & height desired numbers & also change path of image url & image name.
Again after the update everything was working fine with expected & correct result
Hope above code will help you to get same result you expect & we intended.
Thanks & Regards
Mandar Apte