title: Compressing a PNG for use with CIFilter
body: <p>I have an iPhone app that overlays an image over a view created by a XIB, using CIFilter CIHardLightBlendMode. The view is 1000x1000 pixels, and I want to maintain that size until the end. This makes the image files about 1 MB as a png, if there is any complexity. </p>
  
  <p>I've tried using JPGs, but it doesn't overlay the image onto the view on a device (it works on the simulator). I've tried compressing the PNGs, but they get garbled when they get overlaid over the view (they look identical to the full quality ones until they are overlaid). Also, when XCode re-compresses the PNGs to the special iOS version, the compression size savings are lost.</p>
  
  <p>I really would like to compress the files somewhat, but I'm not sure what will work with CIFilter. Any tips?</p>