clean-current-png.ps1

$datastore = "MyDatastore"
$viserver = "MyVIServer"

# add PowerCLI snapin
Add-PSSnapin vmware.vimautomation.core -ErrorAction:SilentlyContinue

# Connect to VI Server
Connect-VIServer $viserver

# Get the datastore we want to clean up
$dsObject = Get-Datastore $datastore

# Create a new PSDrive to that datastore
New-PSDrive -Location $dsObject -name ds -PSProvider VimDatastore -root '\'

# Set location to that drive
Set-Location ds:

# From here we are going to parse through
# folders first looking for vmx files,
# if there are no vmx files,
# test for current.png and then remove the thumbnail and folder.

$dsfolders = Get-ChildItem

foreach ($dsfolder in $dsfolders)
{
    if (!(test-path "$dsfolder\*.vmx"))
    {
        if (test-path "$dsfolder\current.png")
        {
            remove-item "$dsfolder\current.png"
            if ((get-childitem "$dsfolder\*" | measure-object).count -lt 1)
            {
                remove-item $dsfolder
            }
        }
    }
}