NavigationBar Image on iOS 6.1 too large

Question

In my app, I have custom navigation bars using images. I load them up in viewWillAppear like so:

-(void)viewWillAppear:(BOOL)animated {
    UIImage *gradientImage46 = [[UIImage imageNamed:@"navbar2.png"]resizableImageWithCapInsets:UIEdgeInsetsMake(0, 0, 0, 0)];
    [self.navigationController.navigationBar setBackgroundImage:gradientImage46 forBarMetrics:UIBarMetricsDefault];
    [super viewWillAppear:animated];

}

On iOS 7, this is fine, but I just noticed on 6.1, the bar is much too large and looks like this:

Thoughts as to what's happening?