Convert 1 image 2048x2048 to all needed sizes for an iOS app

README.convert_iOS_icon.md

Based on

https://developer.apple.com/design/human-interface-guidelines/ios/icons-and-images/image-size-and-resolution/

Prerequisite

$ brew install imagemagick

This is one way to run this script:

$ time /opt/local/convertappicons/convertappicons.sh AppName.png
AppName

real	0m4.272s
user	0m5.478s
sys	0m0.547s
$ exa -T AppName
AppName
├── Icon-60.png
├── Icon-60@2x.png
├── Icon-60@3x.png
├── Icon-72.png
├── Icon-72@2x.png
├── Icon-76.png
├── Icon-76@2x.png
├── Icon-76@3x.png
├── Icon-iPadPro@2x.png
├── Icon-Small-50.png
├── Icon-Small-50@2x.png
├── Icon-Small.png
├── Icon-Small@2x.png
├── Icon-Small@3x.png
├── Icon-Spotlight-40.png
├── Icon-Spotlight-40@2x.png
├── Icon-Spotlight-40@3x.png
├── Icon.png
├── Icon@2x.png
├── iTunesArtwork
└── iTunesArtwork@2
$ open AppName

Then drag all the files from the newly opened folder on to your app icon grid.

convertAppIconsiOSXCode10.sh

#!/usr/bin/env bash

### Note that if your image is 2048 x 2048 as an example there is no need for -resize to have 2 parameters,
### however if your original image is 4097 x 4095, the 2 parameters will "correct" this.

### https://developer.apple.com/design/human-interface-guidelines/ios/icons-and-images/image-size-and-resolution/

echo ${1%.*}

/bin/mkdir "${1%.*}"

/usr/local/bin/convert "$1" -resize '1024x1024' "${1%.*}/iTunesArtwork@2"
/usr/local/bin/convert "$1" -resize '1024x1024' "${1%.*}/Icon-AppStore-1024.png"
/usr/local/bin/convert "$1" -resize  '512x512'  "${1%.*}/iTunesArtwork"
/usr/local/bin/convert "$1" -resize  '167x167'  "${1%.*}/Icon-iPadPro-83.5@2x.png"
/usr/local/bin/convert "$1" -resize   '76x76'   "${1%.*}/Icon-iPadApp-76.png"
/usr/local/bin/convert "$1" -resize  '152x152'  "${1%.*}/Icon-iPadApp-76@2x.png"
/usr/local/bin/convert "$1" -resize   '80x80'   "${1%.*}/Icon-iPadSpotlight-40@2x.png"
/usr/local/bin/convert "$1" -resize   '40x40'   "${1%.*}/Icon-iPadSpotlight-40.png"
/usr/local/bin/convert "$1" -resize   '58x58'   "${1%.*}/Icon-iPadSettings-29@2x.png"
/usr/local/bin/convert "$1" -resize   '29x29'   "${1%.*}/Icon-iPadSettings-29.png"
/usr/local/bin/convert "$1" -resize   '40x40'   "${1%.*}/Icon-iPadNotifications-20@2x.png"
/usr/local/bin/convert "$1" -resize   '20x20'   "${1%.*}/Icon-iPadNotifications-20.png"
/usr/local/bin/convert "$1" -resize  '180x180'  "${1%.*}/Icon-iPhoneApp-60@3x.png"
/usr/local/bin/convert "$1" -resize  '120x120'  "${1%.*}/Icon-iPhoneApp-60@2x.png"
/usr/local/bin/convert "$1" -resize  '114x114'  "${1%.*}/Icon-iPhoneApp-57@2x.png"
/usr/local/bin/convert "$1" -resize   '57x57'   "${1%.*}/Icon-iPhoneApp-57.png"
/usr/local/bin/convert "$1" -resize  '120x120'  "${1%.*}/Icon-iPhoneSpotlight-40@3x.png"
/usr/local/bin/convert "$1" -resize   '80x80'   "${1%.*}/Icon-iPhoneSpotlight-40@2x.png"
/usr/local/bin/convert "$1" -resize   '87x87'   "${1%.*}/Icon-iPhoneSettings-29@3x.png"
/usr/local/bin/convert "$1" -resize   '58x58'   "${1%.*}/Icon-iPhoneSettings-29@2x.png"
/usr/local/bin/convert "$1" -resize   '29x29'   "${1%.*}/Icon-iPhoneSettings-29.png"
/usr/local/bin/convert "$1" -resize   '60x60'   "${1%.*}/Icon-iPhoneNotifications-20@3x.png"
/usr/local/bin/convert "$1" -resize   '40x40'   "${1%.*}/Icon-iPhoneNotifications-20@2x.png"