How to Update Tenant Corporate Branding for the Entra ID Sign-in Screen with PowerShell

Use Graph SDK Cmdlets to Apply Annual Updates to Corporate Branding for Entra ID Sign-in Screen

Back in 2020, I took the first opportunity to apply corporate branding to a Microsoft 365 tenant and added custom images to the Entra ID web sign-in process. Things have moved on and company branding has its own section in the Entra ID admin center with accompanying documentation. Figure 1 shows some custom branding elements (background screen, banner logo, and sign-in page text) in action.

Entra ID displays the custom elements after the initial generic sign-in screen when a user enters their user principal name (UPN). The UPN allows Entra ID to identify which tenant the account comes from and if any custom branding should be displayed.

Company branding is available to any tenant with Entra ID P1 or P2 licenses. The documentation mentions that Office 365 licenses are needed to customize branding for the Office apps. This mention is very non-specific. I assume it means Office 365 E3 and above enterprise tenants can customize branding to appear in the web Office apps. Certainly, no branding I have attempted has ever affected the desktop Office apps.

Scripting the Annual Branding Refresh

Every year, I like to refresh the custom branding elements, if only to update the sign-in text to display the correct year. It’s certainly easy to make the changes through the Entra ID admin center (Figure 2), but I like to do it with PowerShell because I can schedule an Azure Automation job to run at midnight on January 1 and have the site customized for the year.

The Graph APIs include the organizational branding resource type to hold details of a tenant’s branding (either default or custom). Updating the properties of the organizational branding resource type requires the Organization.Rewrite.All permission. Properties are divided into string types (like the sign-in text) and stream types (like the background image).

The script/runbook executes the following steps:

• Connects to the Graph using a managed identity.
• Retrieves details of the current sign-in text using the Get-MgOrganizationBranding cmdlet.
• Checks if the sign-in text has the current year. If not, update the sign-in text and run the Update-MgOrganizationBranding cmdlet to refresh the setting. The maximum size of the sign-in text is 1024 characters. The new sign-in text should be displayed within 15 minutes.
• Checks if a new background image is available. The code below uses a location on a local disk to allow the script to run interactively. To allow the Azure Automation runbook to find the image, it must be stored in a network location like a web server. The background image should be sized 1920 x 1080 pixels and must be less than 300 KB. Entra ID refuses to upload larger files.
• If a new image is available, update the branding configuration by running the Invoke-MgGraphRequest cmdlet. I’d like to use the Set-MgOrganizationBrandingLocalizationBackgroundImage cmdlet from the SDK, but it has many woes (issue #2541), not least the lack of a content type parameter to indicate the type of image being passed. A new background image takes longer to distribute across Microsoft’s network but should be available within an hour of the update.

Connect-MgGraph -Scopes Organization.ReadWrite.All -NoWelcome 
# If running in Azure Automation, use Connect-MgGraph -Scopes Organization.ReadWrite.All -NoWelcome -Identity

$TenantId = (Get-MgOrganization).Id
# Get current sign-in text
[string]$SignInText = (Get-MgOrganizationBranding -OrganizationId $TenantId -ErrorAction SilentlyContinue).SignInPageText 
If ($SignInText.Length -eq 0) {
   Write-Host "No branding information found - exiting" ; break
}
[string]$CurrentYear = Get-Date -format yyyy
$DefaultYearImage = "c:\temp\DefaultYearImage.jpg"
$YearPresent = $SignInText.IndexOf($CurrentYear)
If ($YearPresent -gt 0) {
    Write-Output ("Year found in sign in text is {0}. No update necessary" -f $CurrentYear)
} Else {
    Write-Output ("Updating copyright date for tenant to {0}" -f $CurrentYear )
    $YearPosition = $SignInText.IndexOf('202')
    $NewSIT = $SignInText.SubString(0, ($YearPosition)) + $CurrentYear
    # Create hash table for updated parameters
    $BrandingParams = @{}
    $BrandingParams.Add("signInPageText",$NewSIT)
    Update-MgOrganizationBranding -OrganizationId $TenantId -BodyParameter $BrandingParams
    If (Test-Path $DefaultYearImage) {
        Write-Output "Updating background image..."
        $Uri = ("https://graph.microsoft.com/v1.0/organization/{0}/branding/localizations/0/backgroundImage" -f $TenantId)
        Invoke-MgGraphRequest -Method PUT -Uri $Uri -InputFilePath $DefaultYearImage -ContentType "image/jpg"
    } Else {
        Write-Output "No new background image available to update"
    }
}

The script is available in GitHub.

Figure 2 shows the updated sign-in screen (I deliberately updated the year to 2025).

If you run the code in Azure Automation, the account must have the Microsoft.Graph.Authentication and Microsoft.Graph.Identity.DirectoryManagement modules loaded as resources in the automation account to use the cmdlets in the script.

Full Corporate Branding Possible

The documentation describes a bunch of other settings that can be tweaked to apply full custom branding to a tenant. Generally, I prefer to keep customization light to reduce ongoing maintenance, but I know that many organizations are strongly attached to corporate logos, colors, and so on.

Corporate Branding for Entra ID Isn’t Difficult

Applying customizations to the Entra ID sign-in screens is not complicated. Assuming you have some appropriate images to use, updating takes just a few minutes with the Entra ID admin center. I only resorted to PowerShell to process the annual update, but you could adopt it to have different sign-in screens for various holidays, company celebrations, and so on.

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