title: How to make scrolling through images as fast as Apple's Photos app
body: <p><em>The Goal</em> — On an iPhone, to browse through several hundred locally-stored jpgs using a UIScrollView.</p>
  
  <p><em>The Problem</em> — Like many others before me, I've tried implementing a scroll view based on Apple's <a href="http://developer.apple.com/iphone/library/samplecode/PageControl/Introduction/Intro.html" rel="nofollow noreferrer">Page Control</a> sample code and found it lacking. The biggest issue I'm currently up against is that the sample code's architecture doesn't seem to scale. With just a few images loaded from disk, everything's fine. Once the number of images gets into the dozens, though, scrolling suffers terribly: the scrollview stutters mid-scroll with each new swipe.</p>
  
  <p>The only code I've toyed with that comes even close to being reasonably responsive is <a href="http://three20.info/" rel="nofollow noreferrer">Three20</a>, but even there the performance doesn't hold a candle to <em>Photos</em>.</p>
  
  <p>For now, I'm just using Three20, but a faster, custom solution would definitely be preferable.</p>