Scale a PNG to required sizes for iOS AppIcons using ImageMagick.

createAppIcon.sh

#!/usr/local/bin/bash

TARGETS=(ipad-notif-1 ipad-notif-2 ipad-settings-1 ipad-settings-2 ipad-spotlight-1 ipad-spotlight-2 ipad-app-1 \
    ipad-app-2 ipad-pro-app-2 itunes)
declare -A NAME=(
    [ipad-notif-1]="iPad Notifications 1x"
    [ipad-notif-2]="iPad Notifications 2x"
    [ipad-settings-1]="iPad Settings 1x"
    [ipad-settings-2]="iPad Settings 1x"
    [ipad-spotlight-1]="iPad Spotlight 1x"
    [ipad-spotlight-2]="iPad Spotlight 2x"
    [ipad-app-1]="iPad App 1x"
    [ipad-app-2]="iPad App 2x"
    [ipad-pro-app-2]="iPad Pro App 2x"
    [itunes]="iTunes / AppStore"
)
declare -A SIZE=(
    [ipad-notif-1]=20
    [ipad-notif-2]=40
    [ipad-settings-1]=29
    [ipad-settings-2]=58
    [ipad-spotlight-1]=40
    [ipad-spotlight-2]=80
    [ipad-app-1]=76
    [ipad-app-2]=152
    [ipad-pro-app-2]=167
    [itunes]=1024
)

mkdir -p Icons
for target in "${TARGETS[@]}"; do
    echo "Resizing to ${SIZE[$target]}x${SIZE[$target]} for ${NAME[$target]}"
    magick convert $1 -resize ${SIZE[$target]}x${SIZE[$target]} Icons/Icon_${SIZE[$target]}.png
done