UIView设置图片（更轻量级，可替代UIImageView）

    UIView *yourView = [[UIView alloc] initWithFrame:CGRectMake(50, 100, 220,220)];
    [self.view addSubview:yourView];
    UIImage *image = [UIImage imageNamed:@"018.png"];
    yourView.layer.contents = (__bridge id)image.CGImage;
    // 设置显示的图片范围
//    yourView.layer.contentsCenter = CGRectMake(0.25,0.25,0.5,0.5);//四个值在0-1之间，对应的为x，y，width，height。