What Icon Display Resolutions and Pixel Densities Should I Use? I am designing an icon for use with an Xcode template and need to know what display-resolution and pixel-density settings I need to use for each of the PNG files I'm exporting from GIMP into my .iconset folder.  Specifically, what display resolutions and pixel densities should I use for the icon_512x512@2x.png, icon_512x512.png, icon_256x256@2x.png, icon_256x256.png, icon_128x128@2x.png, icon_128x128.png, icon_64x64@2x.png, icon_64x64.png, icon_32x32@2x, icon_32x32.png, icon_16x16@2x.png, and icon_16x16.png images in my icon set?
Use the resolution given in the name of the image. For @2x images, double the resolution in both directions. PPI does not matter—Apple uses 72 PPI. Do not use any transparency or interlacing.

For example: icon_512x512@2x.png is a 1024x1024 image.