allilevine

This plugin adds an options page (Settings > Login Screen) that allows you to customize the WordPress Login Screen (wp-login.php). You can:
<ul>
<li>Upload a custom logo (it will be resized to fit if necessary)</li>
<li>Choose a link color</li>
<li>Choose a link rollover color (defaults to a darker shade of the link color)</li>
<li>Choose a button color (defaults to a button version of the link color)</li>
</ul>
The plugin also links the new logo to your site URL.

Simple Login Screen Customizer

Good

Choose a logo and link color for the login screen.  The plugin will do the rest.

Francesco Campus

Tired of manually customizing every wp-login.php page on every website?
Say no more.
Just install and activate FC Login Customizer and let the plugin automagically handle some nice customizations for you!
Core features:
<ul>
<li>Automatically display your brand logo on the website’s login page</li>
<li>Automatically link the logo to the website’s homepage</li>
<li>Automatically change the hidden H1 title to the website’s name</li>
</ul>
Most people do not like that the login screen (wp-login.php) contains the WordPress logo and a direct link to wordpress.org. 
Clients keep asking to change the logo, SEOs keep asking to change the hidden H1 title, UX Designers keep asking to change the link that wraps the login logo… 
With this plugin, you can do all this stuff at once by just installing it!
<h3>What’s next</h3>
Next update may include the additional features listed below:
<ul>
<li>Official support for .svg logos</li>
<li>HTML markup preview before settings save</li>
<li>Fine tuning on logo width/height</li>
<li>Other features based on community requests</li>
</ul>

FC Login Customizer

Automatically customize the login screen with your brand logo, the associated link when clicked and the hidden H1 title inside the page.

Simple Login Screen Customizer vs FC Login Customizer