Creating an image format with an unknown type is an error

Creating an image format with an unknown type is an error とエラーが出ました。画像を表示させ、その画像をサーバーに送るコードを書きました。


import Foundation
import MobileCoreServices
import UIKit
class PhotoController:UIViewController,UINavigationControllerDelegate,UIImagePickerControllerDelegate{

    
    @IBOutlet weak var myActivityIndicator: UIActivityIndicatorView!
    @IBOutlet weak var label: UILabel!
    @IBOutlet weak var myImageView: UIImageView!
    private var imagePicker:UIImagePickerController!
    var textField: UITextField!
    
    @IBAction func uploadButtonTapped(_ sender: Any) {
        myImageUploadRequest()
    }
    override func viewDidLoad() {
        super.viewDidLoad()
        label.adjustsFontSizeToFitWidth = true
        label.minimumScaleFactor = 0.5
        label.text = "Tap the PhotoSelect or Camera to upload a picture"
        myActivityIndicator.hidesWhenStopped = true
     }
    
    @IBAction func PhotoSelect(_ sender: Any) {
        let myPickerController = UIImagePickerController()
        myPickerController.delegate = self;
        myPickerController.sourceType = UIImagePickerControllerSourceType.photoLibrary
        
        self.present(myPickerController, animated: true, completion: nil)


    }
    
    @IBAction func Camera(_ sender: Any) {
        let sourceType:UIImagePickerControllerSourceType = UIImagePickerControllerSourceType.camera
        // カメラが利用可能かチェック
        if UIImagePickerController.isSourceTypeAvailable(UIImagePickerControllerSourceType.camera){
            // インスタンスの作成
            let cameraPicker = UIImagePickerController()
            cameraPicker.sourceType = sourceType
            cameraPicker.delegate = self
            self.present(cameraPicker, animated: true, completion: nil)
            
        }
        else{
            label.text = "error"
            
        }

    }

       
    // 撮影が完了時した時に呼ばれる
    func imagePickerController(_ imagePicker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
        
        if let pickedImage = info[UIImagePickerControllerOriginalImage] as? UIImage {
            myImageView.contentMode = .scaleAspectFit
            myImageView.image = pickedImage
            
        }
        
        //閉じる処理
        imagePicker.dismiss(animated: true, completion: nil)
        label.text = "Tap the Send to save a picture"
        
    }
    
    // 撮影がキャンセルされた時に呼ばれる
    func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
        picker.dismiss(animated: true, completion: nil)
        label.text = "Canceled"
    }

    
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
    //画像のアップロード処理
    func myImageUploadRequest(){
        
        //myUrlにはphpファイルのアドレスを入れる
        let myUrl = NSURL(string:"http://localhost:8000/XXX/");

        let request = NSMutableURLRequest(url:myUrl! as URL)
        request.httpMethod = "POST"
        
        //下記のパラメータはあくまでもPOSTの例
        _ = [
            "userId" : "1234"
        ]
        
        let boundary = generateBoundaryString()
        
        request.setValue("multipart/form-data; boundary=\(boundary)", forHTTPHeaderField: "Content-Type")
        
        let imageData = UIImageJPEGRepresentation(self.myImageView.image!, 1)
        
        if(imageData==nil) { return; }
        let postString = "name=\(textField.text!)"
        request.httpBody = postString.data(using: .utf8)
        
        //myActivityIndicator.startAnimating();
        
        let task = URLSession.shared.dataTask(with: request as URLRequest) {
            data, response, error in
            if error != nil {
                print("error=\(error)")
                return
            }
            // レスポンスを出力
            print("******* response = \(response)")
            let responseString = NSString(data: data!, encoding: String.Encoding.utf8.rawValue)
            print("****** response data = \(responseString!)")
            
            DispatchQueue.main.async(execute: {
                //アップロード完了
            });
        }
        task.resume()
        
    }
    
    func generateBoundaryString() -> String {
        return "Boundary-\(NSUUID().uuidString)"
}

}

上記のコードを実行すると、

objc[7381]: Class PLBuildVersion is implemented in both /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator.sdk/System/Library/PrivateFrameworks/AssetsLibraryServices.framework/AssetsLibraryServices (0x11cdde998) and /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator.sdk/System/Library/PrivateFrameworks/PhotoLibraryServices.framework/PhotoLibraryServices (0x11bcc9880). One of the two will be used. Which one is undefined.
2017-07-18 22:01:26.130891 Kenshin_Swift[7381:434713] [Generic] Creating an image format with an unknown type is an error

とエラーが出ました。image formatの指定をどう直せばよいのでしょうか？どういうコードを追加すればよいのでしょうか？