Josh Byers

The Custom Admin Branding Plugin allows you to brand and customize the WordPress administration area for clients or for personal use. You can display custom images and styles for the login screen, admin header and footer.
It should be fairly easy to use for anyone familiar with WordPress and has basic css and html skills. At its simplest it only requires you to activate and then replace three images with your own. Photoshop templates are included to help you with that.
Get more support on <a href="https://wordpress.org/tags/custom-admin-branding?forum_id=10">the official Custom Admin Branding forum</a>.

Custom Admin Branding

The Custom Admin Branding Plugin allows you to brand and customize the WordPress administration area…

Mateusz Paulski

Plugin adds custom logo widget – images with links.

Logo widget

Plugin adds custom logo widget - images with links.

Custom Admin Branding vs Logo widget