iOS 圆形图片

UIImageView *images = [[UIImageView alloc]initWithFrame:CGRectMake(100, 100, 200, 200)];
images.backgroundColor = [UIColor redColor];
images.image = [UIImage imageNamed:@"1213"];
images.layer.masksToBounds = YES;
images.layer.cornerRadius = CGRectGetHeight(images.bounds)/2;
images.layer.borderWidth = 2.0f;
images.layer.borderColor = [[UIColor lightGrayColor]CGColor];