How to replace the image of the back button entirely with different image?
<p>Below is my coding </p>

<pre><code>// Navigation logic may go here -- for example, create and push another view controller.
NextViewController *nextViewController = 
[[NextViewController alloc] initWithNibName:@"NextViewController" bundle:nil];
[self.navigationController pushViewController:nextViewController animated:YES];
[nextViewController release];

UIImage *backImage=[UIImage imageNamed:@"backbutton.png"]; 
UIBarButtonItem * backBarButtonItem = [[UIBarButtonItem alloc] 
                                       initWithImage:backImage style:UIBarButtonItemStylePlain target:nil 
                                       action:nil]; 
self.navigationItem.backBarButtonItem = backBarButtonItem; 
[backBarButtonItem release];

}
</code></pre>
