Export slides as higher DPI in Microsoft 365 - Powershell

export.ps1

# Load file
$inFile = Read-Host -Prompt '👈 Input File'

# No idea what this does, but it needs it otherwise everything crashes
$officeFalse =  [Microsoft.Office.Core.MsoTristate]::msoFalse
$officeTrue =  [Microsoft.Office.Core.MsoTristate]::msoTrue

# Load Powerpoint Interop Assembly
[Reflection.Assembly]::LoadWithPartialname("Microsoft.Office.Interop.Powerpoint") > $null
[Reflection.Assembly]::LoadWithPartialname("Office") > $null

# start Powerpoint and create file
$application = New-Object "Microsoft.Office.Interop.Powerpoint.ApplicationClass"
$presentation = $application.Presentations.Open($inFile, $officeTrue, $officeFalse, $officeFalse)

# Get what we are trying to load
[int] $slideNumber = Read-Host -Prompt '🔢 Slide number (or 0 for all)'
if ($slideNumber -eq 0) {
    $outFolder = Read-Host -Prompt '👉 Output Folder'
} else {
    $outFolder = Read-Host -Prompt '👉 Output Filename'
    $outFolder = $outFolder + ".png"
}

# Image info
$outFileType = 'PNG'
$dpi = Read-Host -Prompt '🖼 DPI Export'

# Set resolution for DPI stuff
$outResWidth = 1280
$outResHeight = 720

if ($dpi -eq 50) {
    $outResWidth = 667
    $outResHeight = 375
} elseif ($dpi -eq 200) {
    $outResWidth = 2667
    $outResHeight = 1500
} elseif ($dpi -eq 250) {
    $outResWidth = 3333
    $outResHeight = 1875
} elseif ($dpi -eq 300) {
    $outResWidth = 4000
    $outResHeight = 2250
}

# Exporting time
if ($slideNumber -eq 0) {
    # Export everything
    $presentation.Export($outFolder, $outFileType, $outResWidth, $outResHeight)
} else {
    # JUST the slide we want
    $slide = $presentation.Slides.Item(1)
    $slide.Export($outFolder, $outFileType, $outResWidth, $outResHeight)
}

# Cleanup - v important
$slide = $null
$presentation.Close()
$presentation = $null

if($application.Windows.Count -eq 0)
{
	$application.Quit()
}
	
$application = $null
	
# Make sure references to COM objects are released, otherwise powerpoint might not close
# (calling the methods twice is intentional, see https://msdn.microsoft.com/en-us/library/aa679807(office.11).aspx#officeinteroperabilitych2_part2_gc)
[System.GC]::Collect();
[System.GC]::WaitForPendingFinalizers();
[System.GC]::Collect();
[System.GC]::WaitForPendingFinalizers(); 

Seems to only really work in Windows Powershell ISE 🤷‍♂️