Now You can easily add a custom logo to WordPress login page.
I have done it on WordPress 3.5- to 3.5.2. It’s vary easy . Any one can do it . Just go to your web Folder likeYour site/wp-admin/images and Replace wordpress-logo.png And wordpress-logo-2x.pngI have apply it on WordPress 3.5 version .
If you use another version of WordPress and don’t see the two logo on your site/wp-admin/images
Then you can try another way. That also 100% working.
Download your ( your site/wp-admin/images) wp-admin images folder on your Desktop.
Now open the images folder and find the two images under the folder
Now replace the two logo with your custom logo. Be careful don’t change the logo mane . Means your new log and your old logo will be same name.
No more today now enjoy it How-to-add-a-custom-login-register-page-wordpress-without-plugin
Hacking Webdesign WordPress