Swiftメモリ解放のやり方（インスタンス破棄）が分からない..

Swiftで画像をライブラリからUIIMageに読み込み、画面遷移をした際にインスタンスが破棄されずメモリの消費量が上がって、アプリが落ちてしまいます。

Swift
1class StampViewController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate {
2
3    @IBOutlet var imageView:UIImageView!
4
5    @IBAction func camera() {
6        let imagePickController: UIImagePickerController = UIImagePickerController()
7        
8        imagePickController.sourceType = UIImagePickerControllerSourceType.photoLibrary
9        imagePickController.delegate = self
10        imagePickController.allowsEditing = true
11        
12        self.present(imagePickController, animated: true, completion: nil)
13    }
14    
15    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info:
16        
17        [String : AnyObject]) {
18        
19        let image = info[UIImagePickerControllerOriginalImage] as? UIImage
20        self.imageView.image = image
21        self.imageView.image = image
22        self.dismiss(animated: true, completion: nil)
23        }
24//画面遷移⇩
25    @IBAction func Back() {
26        let storyboard: UIStoryboard = self.storyboard!
27        let Started = storyboard.instantiateViewController(withIdentifier: "Started")
28        present(Started, animated: true, completion: nil)
29
30}
31
32
33
34    override func viewDidLoad() {
35        super.viewDidLoad()
36
37
38    }
39
40    override func didReceiveMemoryWarning() {
41        super.didReceiveMemoryWarning()
42
43    }
44    
45}
46
47