Creating Icons for Mac Apps

I found this so helpful on StackOverflow, I thought I’d re-post it here for my personal reference. The snippet below is used to take a 1024-by-1024 pixel PNG file named Icon1024.png, and create smaller resolution copies in an iconset directory, which can be used later when you deploy your app.

mkdir MyIcon.iconset
sips -z 16 16     Icon1024.png --out MyIcon.iconset/icon_16x16.png
sips -z 32 32     Icon1024.png --out MyIcon.iconset/icon_16x16@2x.png
sips -z 32 32     Icon1024.png --out MyIcon.iconset/icon_32x32.png
sips -z 64 64     Icon1024.png --out MyIcon.iconset/icon_32x32@2x.png
sips -z 128 128   Icon1024.png --out MyIcon.iconset/icon_128x128.png
sips -z 256 256   Icon1024.png --out MyIcon.iconset/icon_128x128@2x.png
sips -z 256 256   Icon1024.png --out MyIcon.iconset/icon_256x256.png
sips -z 512 512   Icon1024.png --out MyIcon.iconset/icon_256x256@2x.png
sips -z 512 512   Icon1024.png --out MyIcon.iconset/icon_512x512.png
cp Icon1024.png MyIcon.iconset/icon_512x512@2x.png
iconutil -c icns MyIcon.iconset
rm -R MyIcon.iconset

The next to last line uses the iconutil utility to convert an iconset into an icns file, but it can also work the other way. (See man iconutil for more information.)