Do PNGs (or JPGs) have a DPI? Or is it irrelevant when building for retina?

Question

A simple question that I have been having great difficulty finding a definitive answer to: do PNG files have a DPI? Or perhaps more importantly, is it even relevant when bu

Answer 1

The other answers are correct but may carry too much detail. All that matters is the number of pixels. The dpi will affect how Photoshop or other app might display them but in the end, full screen in non retina is 1024x768 and in retina is 2048x1536. Keep in mind that the iPhone 6 Plus added Retina HD which is 3x.

IF you have enough RAM and a fast enough machine, you may want to create graphics at 3x so you can re sample and save for all three sizes.