I'm a little confused about the resolution here, I know the dimensions suppose to be: 320x480 points but what do I need to put for the resolution? e.g. 300 dpi?

I'm designing on CS5.

  • Flash CS5 or Photoshop CS5? (I have no idea about Flash iOS dev and the Retina display so I don't know if resolution is involved.)
    – BoltClock
    Commented Aug 14, 2011 at 17:52
  • 4
    This doesn't seem to be about programming. The iPhone 4 display is 640×960 at 326 ppi, as documented in many places.
    – andynormancx
    Commented Aug 14, 2011 at 17:53
  • 2
    What you set the PPI/DPI for exported images doesn't matter. iOS ignores this. What matters is that you have the dimensions right (for non-Retina displays), and you exactly double the dimensions for Retina display (iPhone 4). See my answer below. Commented Aug 15, 2011 at 12:43
  • 1
    also, the term points in this context refers to a unit of css measurement specific to the iPhone. You shouldn't be setting anything up in points within PhotoShop...just pixels.
    – DA01
    Commented Aug 15, 2011 at 21:43

2 Answers 2


Should my images be saved at a specific PPI?

No. iOS ignores PPI (pixels per inch) stored inside images. However, the pixel dimensions of your images do matter, so make sure you get those right. It’s also important to ensure your 2× images are exactly double the dimensions of your 1× images and that elements within the image are in the same positions—your Retina images should be identical content to their smaller counterparts, but with more detail.

(via http://bjango.com/articles/designingforretina2/)

Read the above article it's invaluable, if you're designing for iOS. Dimensions matter, the PPI is irrelevant.


iPhone4 retina displays are 960x640 with 326 dpi (ppi). http://en.wikipedia.org/wiki/Retina_display#Display

  • 1
    Found what I was looking for, 326 dpi
    – Yashar
    Commented Aug 14, 2011 at 18:11
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    uh, no yashar...that's the pixel density of the screen. Not any sort of DPI setting for the images you create. In fact, it doesn't matter what DPI setting you use, as it's irrelevant on the screen.
    – DA01
    Commented Aug 15, 2011 at 19:19

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