function Export-MediaFromPptx($pptxFile) 
{
    [void] [System.Reflection.Assembly]::LoadFrom("C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0\WindowsBase.dll")
    $pkg = [System.IO.Packaging.Package]::Open($pptxFile)

    $mediaDirectory = [System.IO.Path]::GetDirectoryName($pptxFile) + "\" + [System.IO.Path]::GetFileName($pptxFile) + "_media"
    md $mediaDirectory | out-null

    foreach ($mediaPart in ($pkg.GetParts() | where { $_.Uri.ToString().StartsWith("/ppt/media/") })) {
      $sourceStream = $mediaPart.GetStream()
      [byte[]]$buffer = new-object byte[] $sourceStream.Length
      [void]$sourceStream.Read($buffer, 0, $sourceStream.Length)
      $sourceStream.Close()
      $targetFileName = $mediaDirectory + "\" + $mediaPart.Uri.ToString().Remove(0, "/ppt/media/".Length)
      [System.IO.File]::WriteAllBytes($targetFileName, $buffer)
    }

    $pkg.Close()
}