param(
    [Parameter(Mandatory)]
    [String]$cacheDir,
    [Int32]$cacheAge=30
);

$cutoff = (Get-Date).AddDays(-$cacheAge);
$allFiles = 0;
$oldFiles = 0;
$freedBytes = 0;
Get-ChildItem -Path $cacheDir -Recurse -File |
where { $_.extension -in '.jpg','.jpeg','.png','.ppm' } |
ForEach {
    $allFiles++;
    if ($_.LastWriteTime -lt $cutoff) {
        $oldFiles++;
        $freedBytes += $_.Length;
        Remove-Item $_.FullName;
    }
};

Write-Output $allFiles;
Write-Output $oldFiles;

if ($freedBytes -gt 1GB) {
    Write-Output "$([math]::round($freedBytes / 1GB, 2)) GiB";
} elseif ($freedBytes -gt 1MB) {
    Write-Output "$([math]::round($freedBytes / 1MB, 2)) MiB";
} elseif ($freedBytes -gt 1KB) {
    Write-Output "$([math]::round($freedBytes / 1KB, 2)) KiB";
} else {
    Write-Output "$($freedBytes) bytes";
}