I have used the code below to create a button on the nav bar with an image.

I can see the image but I can also see the border of the button around it. My question is, how can I get rid of the button border. All I want to see is the image on the nav bar, no border.

UIBarButtonItem *settingsBtn = [[UIBarButtonItem alloc] initWithImage:[UIImage imageNamed:@"icon_prefs.png"] style:UIBarButtonItemStylePlain target:self action:@selector(openSettings:)];
[[self navigationItem] setLeftBarButtonItem:settingsBtn];
[settingsBtn release];

Thanks in advance. Any pointers, links to read further or examples appreciated.