João Luís

WordPress allows you to define a site logo (through Jetpack) and a site icon, why would you need to upload another image to use in your login page?
This plugin allows you to forget the login page. Just activate it and all the magic is done for you. No extra steps required.
The plugins uses the site logo if it exists, otherwise it will use the site icon. If none of them exist, the plugin will not touch your login page.

JL Login Logo

Uses your site logo (defined through Jetpack) or your site icon as the logo on the login form.

Brandon Kraft

Jetpack automatically disables its Open Graph tags when there’s a known plugin that already adds Open Graph tags, which is good. Sometimes, though, you might want to use Jetpack’s version instead. Even if you disable the tags in the conflicting plugin, Jetpack won’t add Open Graph tags without being told to do so.
This is great for when you want to use the awesome WP SEO by Yoast plugin or others like All-in-One SEO, but, for whatever reason, would like to use Jetpack’s OG tags instead.

Always Use Open Graph with Jetpack

Jetpack automatically disables its Open Graph tags when there's a known plugin that already adds Open Graph tags, which is good.

JL Login Logo vs Always Use Open Graph with Jetpack