//圆角设置imageView.layer.cornerRadius = 8;(值越大，角就越圆)imageView.layer.masksToBounds = YES;//边框宽度及颜色设置[imageView.layer setBorderWidth:2];[imageView.layer setBorderColor:[UIColor blueColor]];  //设置边框为蓝色//自动适应,保持图片宽高比imageView.contentMode = UIViewContentModeScaleAspectFit;