win11profilepic.ps1

$script = {
    param(
        [Parameter()]
        [string]$sid,
        [Parameter()]
        [string]$url
    )

    # Generate a unique prefix
    $prefix = [guid]::NewGuid().ToString("B").ToUpper()

    # Download a profile photo
    $downloadFilePath = "$Env:TEMP\$prefix.jpg"
    Invoke-WebRequest -Uri $url -OutFile $downloadFilePath

    # Load the photo into memory
    Add-Type -AssemblyName "System.Drawing"
    $photo = [System.Drawing.Image]::FromFile($downloadFilePath)

    # Create the quality parameter we will use for resizing the photo
    $encoder = [System.Drawing.Imaging.Encoder]::Quality
    $quality = 90
    $parameters = [System.Drawing.Imaging.EncoderParameters]::new()
    $parameters.Param[0] = [System.Drawing.Imaging.EncoderParameter]::new($encoder, $quality)

    # Get an image encoder for photos
    $codec = [System.Drawing.Imaging.ImageCodecInfo]::GetImageEncoders() | Where-Object { 
        $_.MimeType -eq "image/jpeg"
    }

    # This is the path to a folder inside the special account pictures folder
    $destinationDirectoryPath = "$Env:PUBLIC\AccountPictures\$sid"
    if (Test-Path $destinationDirectoryPath)
    {
        Remove-Item -Force -Path $destinationDirectoryPath -Recurse
    }
    $directory = New-Item -ItemType Directory -Path $destinationDirectoryPath

    # This is the path in the Windows Registry
    $keyPath = "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\AccountPicture\Users\$sid"
    if (-not (Test-Path $keyPath))
    {
        $key = New-Item -ItemType Directory -Path $keyPath
    }

    # Create a new file for each size
    foreach ($size in $(32, 40, 48, 64, 96, 192, 208, 240, 424, 448, 1080))
    {
        # Draw the original photo onto a bitmap
        $bitmap = [System.Drawing.Bitmap]::new($size, $size)
        $graphics = [System.Drawing.Graphics]::FromImage($bitmap)
        $graphics.InterpolationMode = [System.Drawing.Drawing2D.InterpolationMode]::HighQualityBicubic

        $graphics.Clear([System.Drawing.Color]::White)
        $graphics.DrawImage($photo, 0, 0, $size, $size)

        # Save the bitmap
        $destinationFilePath = "$destinationDirectoryPath\$prefix-Image$size.jpg"
        $bitmap.Save($destinationFilePath, $codec, $parameters)
        $bitmap.Dispose()

        # Register the saved file in the Windows Registry
        $value = New-ItemProperty -Force `
            -Name "Image$size" `
            -Path $keyPath `
            -PropertyType "String" `
            -Value $destinationFilePath
    }

    # Dispose the photo
    $photo.Dispose()

    # Delete the downloaded file
    Remove-Item -Force -Path $downloadFilePath
}

# Get current user's SID
$user = Get-LocalUser -Name $Env:USERNAME
$sid = $user.SID.Value

# Get the URL of a photo to use as the account picture
# TIP: share it locally with python -m http.server
$url = "https://localhost/profilepic.jpg"

# Run the script block above as SYSTEM, passing in the SID
Invoke-CommandAs -AsSystem -ScriptBlock $script -ArgumentList $sid,$url

Adjust the value of $url as needed & run as admin. (jpg only)