我强烈建议您使用NINetworkImageView https://github.com/jverkoey/nimbus 项目。
这很轻，很有用。
我有一个委托方法，让你知道什么时候加载图像。
你基本上需要做的是：
1.为每个页面创建一个NINetworkImageView，就像你使用UIImageView一样，调用set

I highly suggest you use NINetworkImageView from https://github.com/jverkoey/nimbus project. It's very light and useful. I has a delegate method to let you know when an image is loaded. What you basically need to do is: 1. create an NINetworkImageView for each page, just like you do with UIImageView, and call set

  NINetworkImageView* networkImageView = [[[NINetworkImageView alloc] initWithImage:initialImage]
                                      autorelease];
  networkImageView.delegate = self;
  networkImageView.contentMode = UIViewContentModeCenter;
[networkImageView setPathToNetworkImage:
     @"http://farm3.static.flickr.com/2484/3929945380_deef6f4962_z.jpg"
                             forDisplaySize: CGSizeMake(kImageDimensions, kImageDimensions)];

https://github.com/jverkoey/nimbus/tree/master/examples/photos/NetworkPhotoAlbums

1. 将指示器添加到networkImageView作为子视图。



2. 实现委托如下：

1. the add the indicator to the networkImageView as a subview.

2. implement the delegate as follows:

- （void）networkImageView：（NINetworkImageView *）imageView didLoadImage：（UIImage *）image {
[imageView removeAllSubviews];

-(void)networkImageView:(NINetworkImageView *)imageView didLoadImage:(UIImage *)image { [imageView removeAllSubviews];

}

更小的代码来做同样的事情。

the end result would be a much smaller code for doing the same thing.