How to write a custom initializer that prevents viewDidLoad being called?
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
  self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
  if ( self ) {

  }
  return self;
}

- (id) initWithFilename:(NSString *)aFilename {
  self = [self initWithNibName:@"WallpaperDetailsViewController" bundle:nil];
  if ( self ) {
    self.filename = aFilename;
  }
  return self;
}

- (void)viewDidLoad {
  [super viewDidLoad];

  // Create a UIImageView to display the wallpaper
  self.wallpaper = [[UIImageView alloc] initWithImage:[UIImage imageNamed:self.filename]];
  // ...
}

WallpaperDetailsViewController *detailsViewController = [[WallpaperDetailsViewController alloc] initWithFilename:@"foobar.png"];
[[self navigationController] pushViewController:detailsViewController animated:YES];

- (id) initWithFilename:(NSString *)aFilename {
  // Call super's designated initializer
  self = [super initWithNibName:@"WallpaperDetailsViewController"
                         bundle:nil];
  if ( self ) {
    self.filename = aFilename;
  }
  return self;
}

- (id) initWithFilename:(NSString *)aFilename {
   self = [self initWithNibName:@"WallpaperDetailsViewController" bundle:nil];
   if ( self ) {
      filename = [aFilename retain];
      wallpaper = [[UIImageView alloc] initWithImage:[UIImage imageNamed:aFileName]];
   }
   return self;
}