aserogin

# Root path to look 'orphan' items under - update here as needed
cd 'master:/sitecore/media library'

$counter = 0
$itemsToProcess = Get-ChildItem -Recurse . | Where-Object { $_.TemplateName -ne 'Media Folder' }  
if ($itemsToProcess -ne $null) {
    $itemsToProcess | ForEach-Object {
        $referrers = Get-ItemReferrer -Item $_ | measure
        if ($referrers.Count -eq 0) {
            $counter++