Image Loading and Caching

var imageCache = [String : UIImage]()


var image = self.imageCache[urlString]
       
       
        if( image == nil ) {
            // If the image does not exist, we need to download it
            var imgURL: NSURL = NSURL(string: urlString)
           
            // Download an NSData representation of the image at the URL
            let request: NSURLRequest = NSURLRequest(URL: imgURL)
            NSURLConnection.sendAsynchronousRequest(request, queue: NSOperationQueue.mainQueue(), completionHandler: {(response: NSURLResponse!,data: NSData!,error: NSError!) -> Void in
                if error == nil {
                    image = UIImage(data: data)
                   
                    // Store the image in to our cache
                    self.imageCache[urlString] = image
                    dispatch_async(dispatch_get_main_queue(), {
                        if let cellToUpdate = tableView.cellForRowAtIndexPath(indexPath) {
                            cellToUpdate.imageView?.image = image
                        }
                    })
                }
                else {
                    println("Error: \(error.localizedDescription)")
                }
            })
           
        }
        else {
            dispatch_async(dispatch_get_main_queue(), {
                if let cellToUpdate = tableView.cellForRowAtIndexPath(indexPath) {
                    cellToUpdate.imageView?.image = image
                }
            })
        }



NOTE:This is in swift programming.