废话不多说，直接上代码！

创建imageView的时候这么写就OK

    UIImageView *imgV_proPic = [[UIImageView alloc]initWithFrame:CGRectMake(15, 15, 100, 100)];
    imgV_proPic.backgroundColor = [UIColor orangeColor];
    [self.contentView addSubview:imgV_proPic];
    [imgV_proPic setContentScaleFactor:[[UIScreen mainScreen] scale]];
    imgV_proPic.contentMode =  UIViewContentModeScaleAspectFill;
    imgV_proPic.clipsToBounds  = YES;

小伙伴们可以试一下~