Why is the logo selected for the wp-login.php page not rendering correctly?

I've used the Ultimate Branding successfully on the wp-login.php page for two websites. They are http://cchwb.org/wp-admin and http://blackmothersunited.org/wp-admin, but the image I selected for http://wsbydesign.com.wsbydesign/wp-admin is not rendering properly on the page although it looks just fine in the Ultimate Branding dashboard. It's squished. In fact when I revert back to the WordPress logo, it is also squished.

Can you help me find a solution for this please?

Thanks so much!