Question

I want to add an image background to my navigation bar.

Is it right?

//set custom background image
UIImageView *backgroundView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"NavigationBackground.png"]];
[self.navigationBar insertSubview:backgroundView atIndex:0];
[backgroundView release];

Answer 1

Here’s the code from the link @luvieere mentioned.
Paste this code into to the rootview controller just above
@implementation rootviewController

@implementation UINavigationBar (CustomImage)
- (void)drawRect:(CGRect)rect {
    UIImage *image = [UIImage imageNamed:@"NavigationBar.png"];
    [image drawInRect:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
}
@end

As of iOS 5, there is an official way to do this. (see iOS Developer Library)

// someplace where you create the UINavigationController
if ([navigationController.navigationBar respondsToSelector:@selector(setBackgroundImage:forBarMetrics:)] ) {
    UIImage *image = [UIImage imageNamed:@"NavigationBar.png"];
    [navigationBar setBackgroundImage:image forBarMetrics:UIBarMetricsDefault];
}

But still, retain the old code for backward compatibility unless you really want to ditch iOS 4 and below.