Note:: This is a license parameter and only available if you have purchased the license for re-branding the UI.
You can change the logo for OEM branding on a per organization level by clicking on the Update Theme in the Administration > Organization menu for a organization or an admin group.
You can also define a custom URL for a organization , so that the login page displays a different logo for each organization (or customer in the case of MSPs).
The logo change also applies to the MFA login page.