     }
     
     fileprivate func permanentCacheFileURL(key: String, variant: Int64) -> URL {
-        return self.permanentStorageDirectory.appendingPathComponent("\(key)::\(variant)", isDirectory: false)
+        return self.permanentStorageDirectory.appendingPathComponent("\(key)||\(variant)", isDirectory: false)
     }
     
     fileprivate func fetchCacheItem(key: String, variant: Int64, moc: NSManagedObjectContext) -> CacheItem? {

    }
    
    fileprivate func createCacheItem(key: String, variant: Int64, moc: NSManagedObjectContext) -> CacheItem? {
        guard let item = NSEntityDescription.insertNewObject(forEntityName: "CacheItem", into: moc) as? CacheItem else {
            return nil
        }
        item.key = key
        item.variant = variant
        item.date = NSDate()

        guard let siteURL = (url as NSURL).wmf_site, let imageName = WMFParseImageNameFromSourceURL(url) else {
            return nil
        }
        return siteURL.absoluteString + "||" + imageName
    }
    
    fileprivate func variantForURL(_ url: URL) -> Int64 { // A return value of 0 indicates the original size
