iOS App background not displaying when inserting in code form rather than storyboard

//
//  ViewController.h
//  CrystalBall
//
//  Created by James E. Rawls, Jr. on 4/7/13.
//  Copyright (c) 2013 James E. Rawls, Jr. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController {
    NSArray *predictionArray;
    NSArray *myColorsArray;
}


@property (strong, nonatomic) IBOutlet UILabel *predictionLabel;
@property (strong, nonatomic) NSArray *predictionArray;
@property (strong, nonatomic) NSArray *myColorsArray;

- (IBAction)buttonPressed:(UIButton *)sender;


@end

----------------------------------------------------------------------------------------------------------------------

//
//  ViewController.m
//  CrystalBall
//
//  Created by James E. Rawls, Jr. on 4/7/13.
//  Copyright (c) 2013 James E. Rawls, Jr. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController
@synthesize predictionLabel;
@synthesize predictionArray;
@synthesize myColorsArray;


- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    UIImage *image = [UIImage imageNamed:@"background.png"];
    UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
    [self.view insertSubview:imageView aboveSubview:0];

    self.predictionArray = [[NSArray alloc] initWithObjects:
                                @"It is certain",
                                @"It is decidely so",
                                @"All signs say YES",
                                @"The stars are not aligned",
                                @"My reply is no",
                                @"It is doubtful",
                                @"Better not tell you now",
                                @"Concentrate and ask again",
                                @"Unable to answer now",
                                @"Maybe yes",
                            nil];
    self.myColorsArray = [[NSArray alloc] initWithObjects:
                                [UIColor redColor],
                                [UIColor blueColor],
                                [UIColor blackColor],
                                [UIColor yellowColor],
                                [UIColor orangeColor],
                                [UIColor purpleColor],
                                [UIColor brownColor],
                            nil];
}

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

- (IBAction)buttonPressed:(UIButton *)sender {
    NSUInteger index = arc4random_uniform(self.predictionArray.count);
    NSUInteger myColor = arc4random_uniform(self.myColorsArray.count);

    self.predictionLabel.text = [self.predictionArray objectAtIndex:index];
    self.predictionLabel.textColor = [self.myColorsArray objectAtIndex:myColor];

}
@end