In my app I have applied an image on uinavigation item. It is running fine in iOS 5 but getting expanded on iOS 6. I have no left or right bar button item in navigation bar.
I have the following code in my project, and works fine under iOS 5 and iOS 6. Can you try this:
self.navigationItem.titleView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"topNav-logo.png"]];
Also, be sure to have both @2x and regular sizes of the image.