Would somebody please clarify this for me? The iPhone 4 has a resolution of 640 x 1136px so if I wanted a square icon, for example, to take up half of the screen, the PNG should still be 640 x 640px because it will be downsized by half? Or do I just create a 640 x 1136px canvas and however it appears there is how it will appear once uploaded on the app?

  • You make your images twice as big to work on 2x screens. Whether you create the entire canvas or not would depend on how the app is being built.
    – DA01
    Dec 10, 2015 at 23:32
  • Is there any way to control or prevent a 2x image from downsizing and showing partial pixels for straight lines? Dec 10, 2015 at 23:41
  • Are you working in Xcode or in browser? I'm assuming you're coding in Xcode - in which case this documentation will help.
    – Bento
    Dec 11, 2015 at 2:36

1 Answer 1


640 × 1136 px² is already the 1:1 resolution, meaning these are physical pixels of the screens.

So yes, you create a 640 × 1136 canvas, create your icon in the dimensions that you desire, and then crop it out.

Your final icon file should have the dimensions of 320 × 320 px².

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