快速将图像转换为 BASE64 字符串

我正在尝试转换用户从他的照片或从相机中选取的图像。我能够将图像转换为 base64 字符串，但问题是它需要太多时间并打印一个长的无限字符串

这是我得到的字符串的输出

这是我的代码：

// Image picker from Gallery
    func imagePickerController(picker: UIImagePickerController, didFinishPickingImage image: UIImage, editingInfo: [String : AnyObject]?) {
        imagePicker.dismissViewControllerAnimated(true, completion: nil)
        profileImage.image = image

    }

    // Image Picker from Camera

    func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]) {
        imagePicker.dismissViewControllerAnimated(true, completion: nil)
        profileImage.image = info[UIImagePickerControllerOriginalImage] as? UIImage

        addPicBtn.setImage(nil, forState: .Normal)

        let imageData:NSData = UIImagePNGRepresentation(profileImage.image!)!
        let imageStr = imageData.base64EncodedStringWithOptions(NSDataBase64EncodingOptions(rawValue: 0))
        print(imageStr)


    }

实际上转换不需要时间，但是打印会花费更多时间，所以不要打印......