Swift: Maintain cache for url images

hi everyone,

I am new to SWIFT.

So how to store url images in locally i.e iOS App.

I follow the popular API called SDWebImage, for this I am following steps.

Step1:

get json response from the server via mutable request using with dataTaskWithRequest.

Step2:

2.1: Added SDWebImageView framework to my project

2.1: Then call custom method in the class UIImageView +WebCache

imageView.sd_setImageWithURL(url,

placeholderImage: UIImage(named: "placeholder.png"),

options:SDWebImageOptions.RefreshCached)

is implemented in cellForItemAtIndexPath under custom UICollectionView class.

Step 3: Everything is fine images are loading in the collection view.

NOW I want to show the images again in another view or itself ?

At this time how can I know that those images are either coming from the Server or from Cache in local ?

Thanks in advance

Srikanth