Xcode - how to dismiss modal UIImageView?

Very new to iOS development. I'm trying to make an thing that will let me select a photo from the photo library, and display it. I'm using a storyboard with a navigation controller. I'm able to select and display the image just fine, but I can't figure out how to dismiss the imageview and return back to the image picker. I just get a fullscreen image and cant click anywhere to do anything. Code looks like this:

snapViewController.h 

#import <UIKit/UIKit.h>

@interface snapViewController : UIViewController <UIImagePickerControllerDelegate,
UINavigationControllerDelegate> 

@property (strong, nonatomic) IBOutlet UIImageView *ImageView;

- (IBAction) done:(UIStoryboardSegue *)unwindsegue;

@end

My .m

snapViewController.m 


#import "snapViewController.h"

@interface snapViewController ()

@end

@implementation snapViewController


- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}
- (BOOL)prefersStatusBarHidden {
    return YES;
    [self setNeedsStatusBarAppearanceUpdate];
}


- (void) viewDidAppear:(BOOL)animated{
    [super viewDidAppear:animated];
    if (self.ImageView.image == nil){
        UIImagePickerController * imagePickerController = [UIImagePickerController new];
        imagePickerController.modalPresentationStyle = UIModalPresentationCurrentContext;
        imagePickerController.delegate = self;
        [self presentViewController:imagePickerController animated:NO completion:nil];
    }
    else {

    }



}

- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker{
    [self dismissViewControllerAnimated:YES completion:nil];

}

- (void) imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
    UIImage *image = [info valueForKey:UIImagePickerControllerOriginalImage];
    self.ImageView.image = image;
    [self.ImageView setUserInteractionEnabled:YES];
    [self dismissViewControllerAnimated:YES completion:nil];


}

- (IBAction) done:(UIStoryboardSegue *)unwindsegue {


}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}



@end

Storyboard looks like this, I stuck a toolbar on the bottom of the UIImageView with a done button: Do I need to bind the done button to the [self dismissViewControllerAnimated:YES completion:nil]; action? How can I do this? I've been struggling with this for a couple hours and can't figure it out. Thanks.