使用ImageView

@property (strong, nonatomic) UIPopoverController *pop;

//选取图片
- (IBAction)selectImage:(UIButton *)sender
{
    UIImagePickerController *picker = [[UIImagePickerController alloc] init];
    if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary])
    {
        picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
        picker.delegate = self;
        
        self.pop = [[UIPopoverController alloc] initWithContentViewController:picker];
        self.pop.delegate = self;
        [self.pop presentPopoverFromRect:sender.frame inView:self.view permittedArrowDirections:UIPopoverArrowDirectionAny animated:YES];
    }
}

-(void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
{
    [self.pop dismissPopoverAnimated:YES];
}

-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    UIImage *image = [info valueForKey:@"UIImagePickerControllerOriginalImage"];
    self.masterViewController.mainImage = image;
    self.imageView.image = image;
    [self.pop dismissPopoverAnimated:YES];
}

- (IBAction)clearImage:(id)sender
{
    self.imageView.image = nil;
    self.masterViewController.mainImage = nil;
}