generate-iOS-app-icons.sh

#!/bin/bash
# usage :
#   generate-iOS-app-icons.sh someDir/sourceImage-1024x1024.png path/where/ImagesAssets/is/located

mkdir -p generated
# you'll have to delete this one after executing the script if you copy the generated images in the Images asset
 
SOURCE_ICON="$1"
PATH_TO_IMAGES_ASSET="$2"

listOfSizes="29 58 80 57 114 120 180 40 50 100 72 144 76 152"

for imageSize in $listOfSizes
do
  sips -Z ${imageSize} --out generated/icon${imageSize}.png "${SOURCE_ICON}"
done

cp generated/*.png "${PATH_TO_IMAGES_ASSET}/Images.xcassets/AppIcon.appiconset"

# you'll have to modify the content.json or do it in XCode...

############# For reference, below the original gist content, which size applies to what :

#sips -Z 29 --out generated/iPhoneSettings-29x29.png ${SOURCE_ICON}
#sips -Z 58 --out generated/[email protected] ${SOURCE_ICON}
#sips -Z 80 --out generated/[email protected] ${SOURCE_ICON}
#sips -Z 57 --out generated/iPhoneIOS6App-57x57.png ${SOURCE_ICON}
#sips -Z 114 --out generated/[email protected] ${SOURCE_ICON}
#sips -Z 120 --out generated/[email protected] ${SOURCE_ICON}
#sips -Z 180 --out generated/[email protected] ${SOURCE_ICON}

#sips -Z 29 --out generated/iPadSettings-29x29.png ${SOURCE_ICON}
#sips -Z 58 --out generated/[email protected] ${SOURCE_ICON}
#sips -Z 40 --out generated/iPadSpotlight-40x40.png ${SOURCE_ICON}
#sips -Z 80 --out generated/[email protected] ${SOURCE_ICON}
#sips -Z 50 --out generated/iPadSpotlightIOS6-50x50.png ${SOURCE_ICON}
#sips -Z 100 --out generated/[email protected] ${SOURCE_ICON}
#sips -Z 72 --out generated/iPadAppIOS6-72x72.png ${SOURCE_ICON}
#sips -Z 144 --out generated/[email protected] ${SOURCE_ICON}
#sips -Z 76 --out generated/iPadApp-76x76.png ${SOURCE_ICON}
#sips -Z 152 --out generated/[email protected] ${SOURCE_ICON}

Added command line parameters, and streamlined the generation of images to what XCode uses ("iconXXX.png").