title: UIImage initWithContentsOfFile: and caching
body: <p>I'm creating a UIView similar to <a href="http://developer.apple.com/library/ios/#samplecode/Scrolling/Introduction/Intro.html%23//apple_ref/doc/uid/DTS40008023-Intro-DontLinkElementID_2" rel="nofollow">Apple's Scrolling</a> example and I have a question regarding UIImage and caching; I don't know if I fully understand the practical implications of the Apple Documentation.</p>
  
  <p>The <a href="http://developer.apple.com/library/ios/#documentation/uikit/reference/UIImage_Class/Reference/Reference.html" rel="nofollow">docs</a> say:</p>
  
  <blockquote>
    <p><strong>Discussion</strong>
    This method loads the image data into memory and marks it as purgeable. If the data is purged and needs to be reloaded, the image object loads that data again from the specified path.</p>
  </blockquote>
  
  <p>In practice, what does this mean? </p>
  
  <p>I'm reading it like this: If the system is running low on memory, UIImages that aren't being shown on screen are purged, and reloaded from the file specified when needed.</p>
  
  <p>At the moment I'm loading quite a few images and I'm concerned about memory management; it would be great if I can just leave the system to purge / cache as it sees fit, but I doubt that this is an effective solution. I'd appreciate any pointers / clarifications. </p>