title: On iOS, since dataWithContentsOfURL:options:error: has an option to not cache data, does that mean dataWithContentsOfURL caches data?
body: <p>The option to not cache data is <code>NSDataReadingUncached</code>.</p>
  
  <p>But if I use <code>dataWithContentsOfURL</code> to update the images from URLs in a <code>UITableViewCell</code> (one image per cell), and I look at the Activities Monitor on the Mac for the Simulator (running as iOS 5.1 simulator), then the network traffic jumps up to 12kb/s receiving rate when I scroll the table up and down continuously.  When I stopped scrolling up and down, the network activities drops down to about 2kb/s receiving rate or lower.  Those images are very small, like 20kb or so each, and when I scroll up and down, I only make 1 or 2 image disappear / appear, so the cache, if any, won't need to be large at all.</p>
  
  <p>So it does look like <code>dataWithContentsOfURL</code> does not cache data, and even when I use <code>dataWithContentsOfURL:options:error:</code> with options being <code>0</code> to mean no option, the network activities still jump up to about 12kb/s.</p>
  
  <p>So does <code>dataWithContentsOfURL</code> caches data, and if not, why does <code>dataWithContentsOfURL:options:error:</code> has the option of not cache data?</p>
  
  <p>The following is also done:</p>
  
  <pre><code>[[NSURLCache sharedURLCache] setMemoryCapacity:1024*1024*10];
  </code></pre>
  
  <p>in <code>viewDidLoad</code> but the network rate still will jump up.  I think the usual recommendation is that if caching is desired, then use <code>NSURLConnection</code>, but for some reason, in the <code>NSURLConnection</code> reference on Apple's doc, the word "cache" or "caching" doesn't appear at all except there is mentioning of a sample project called "URLCache", but no mentioning of caching at all.</p>