title: iOS: how to reduce size of large PNG files
body: <p>I'm currently optimizing my iOS app for <em>the new iPad</em>. Unfortunately by adding launch images for the iPad retina display the size of my <em>ipa</em> grows from 1.2MB to 5.5MB, mainly because of the two PNG images in 1536 x 2008 (portrait) and 2048 x 1496 (landscape). The size of these images are respectivly 1.9MB and 1.7MB.</p>
  
  <p>The portrait can be seen here: <a href="http://uploads.demaweb.dk/iPadPortrait.png">http://uploads.demaweb.dk/iPadPortrait.png</a>.</p>
  
  <p>As you may notice, the background is a fixed pattern but sadly it seems that this is not very compressible. I've further tried to compress the images using <a href="http://imageoptim.com/">ImageOptim</a>, but it does not make any difference after Xcode has compressed the images during the archive. Searching the web I've noticed, that some people are dissuading to turn off PNG compressing in Xcode.</p>
  
  <p>Are there anything I can do? It is not a solution to change the pattern in the image to a solid color, as it should look like the background in my iOS view. But it seems odd, that supporting <em>the new iPad</em> increase the size by ~4MB.</p>