Expose Branding - Enable Branding Automation via Powershell
Currently only Domain Admins can update the sign-in page illustration and must be done through the GUI.
I'd suggest exposing cmdlets through Powershell similar like "Set-UserPhoto" so this could be automated or scheduled.
It isn't optimal to manually update this regularly nor add a marketing/creative team member to have access to Azure AD to empower them to make these changes.
Thomas Stensitzki commented
This is a must have requirement.