António Campos

With this plugin you can easily choose one image from your gallery and use it as logo in your wp-login.php

AC Change Login Image

This plugin changes the image in the login page (wp-login.php), you can choose any image from your gallery and use it as login logo.

prontotools

zkancs

Do some or all of the websites in your multisite network require a custom login logo? Well now you’re in luck!
This plugin allows you to customize the login logo per site, with the option to use the network’s default logo as well.
Once installed, access your theme’s Customize settings to update the logo.
Here is our <a href="https://github.com/prontotools/multisite-login-logos" title="Fork" rel="nofollow ugc">Git repository</a>. Feel free to contribute!

Multisite Login Logos

Easily change the logo on a network site's WP login screen using WordPress's Customize settings.

AC Change Login Image vs Multisite Login Logos