Sample PowerShell script that shows you how to create a .BMP file of the display of a Hyper-V virtual machine.

SaveVMBitmap.ps1

$VMName = "VM 1"
$BMPName = "C:\Users\benja\Desktop\test.bmp"

Add-Type -AssemblyName "System.Drawing"
 
$VMCS = Get-WmiObject -Namespace root\virtualization\v2 -Class Msvm_ComputerSystem -Filter "ElementName='$($VMName)'" 

# Get the resolution of the screen at the moment
$video = $VMCS.GetRelated("Msvm_VideoHead")
$xResolution = $video.CurrentHorizontalResolution[0]
$yResolution = $video.CurrentVerticalResolution[0]

function getVMScreenBMP {
    param
    (
        $VM,
        $x,
        $y
    )

    $VMMS = Get-WmiObject -Namespace root\virtualization\v2 -Class Msvm_VirtualSystemManagementService

    # Get screenshot
    $image = $VMMS.GetVirtualSystemThumbnailImage($VMCS, $x, $y).ImageData

    # Transform into bitmap
    $BitMap = New-Object System.Drawing.Bitmap -Args $x,$y,Format16bppRgb565
    $Rect = New-Object System.Drawing.Rectangle 0,0,$x,$y
    $BmpData = $BitMap.LockBits($Rect,"ReadWrite","Format16bppRgb565")
    [System.Runtime.InteropServices.Marshal]::Copy($Image, 0, $BmpData.Scan0, $BmpData.Stride*$BmpData.Height)
    $BitMap.UnlockBits($BmpData)

    return $BitMap
}

(getVMScreenBMP $VMCS $xResolution $yResolution).Save($BMPName)

Awesome, works great still on Server 2019 :)

This is supposed to be run on the host machine, not inside the guest machine, right?

I can confirm this works on Windows PowerShell, but not modern PowerShell (powershell.exe, not pwsh.exe), at least on my machine. This is awesome!

EDIT (18 June 2024): The code as-is only works in Windows PowerShell, but that's because there are newer APIs for using WMI/CIM in modern PowerShell.

For my purposes, I used runspaces to continue using the old APIs, but you can see a modern implementation in strawgate's HyperV-OCR project (a friend found that for me).

Runspace alternative:

$s = New-PSSession -UseWindowsPowerShell
Invoke-Command -Session $s -ScriptBlock {
  # Call above code, basically.
  #
  # If you want to reference external variables:
  # $MyVar becomes $using:MyVar
}