how to set round corners in images in iphone

Merged with How to set round corners in UI images in iphone. 开发者_JAVA技巧

I need to set image to button image should be in rounded corner

[camBtn setImage:[UIImage imageNamed:@"camera.png"] forState:UIControlStateNormal];

cambtn should be button i need @"camera.png" should be rounded corners plz help i how to write