Remove unused media items

Remove-UnusedMediaItems.ps1

#Include all paths you do not want to analyse below 
$protectedPaths = @(
    "/sitecore/media library/System/", 
    "/sitecore/media library/Experience Explorer"
    "/sitecore/media library/Images/Social"
    );
    
#Include all item templates you want to ignore in the array below
$protectedTemplates = @(
    [Sitecore.TemplateIDs]::MediaFolder
    );

$itemsToDelete = 
    Get-ChildItem -Path "master:\sitecore\media library" -Recurse |

        # filter out items of templates you do not want to touch
        Where-Object { $_.TemplateID -notin $protectedTemplates } |

        # do not allow items in the protected paths
        Where-Object { 
            $item = $_; 
            $protected = $protectedPaths | Where-Object { ($item.Paths.Path) -match $_ };
            $protected.Count -lt 1;
        } | 

        # and only items that are not used
        Where-Object { [Sitecore.Globals]::LinkDatabase.GetReferrerCount($_) -eq 0 }

#List the items
$itemsToDelete | ft ProviderPath

#If the list above looks like what you want to delete you can uncomment the following line
#$itemsToDelete | Remove-Item

Sweet!