macOS preparing assets: which file format appropriate for 160ppi?

[technekai]

i am preparing assets for an iPhone app built with the SDK. in which format should i save the images, in order to take advantage of the iPhone screen resolution of 160ppi? native Photoshop format is not an option, my programmer does not have it.

TIFF at 160ppi?

thank you for your advice,
aya.

 

[Nutter]

PNG is the recommended format.

You should save your images at 72dpi if you want one pixel in the image to correspond to one pixel on the iPhone.

 

[HiRez]

I find that PNG generally has better compression than TIF, I only use TIF when I need multiple alpha channels or layers. For graphics productions I also recommend rendering intermediate QuickTime movies using the QuickTime PNG rather than the Animation codec.

 

[Nutter]

Xcode also performs additional (non-lossy) compression on PNGs at compile time, and iPhone OS apparently has an optimised pathway for PNG decompression, so it's a winner all round.