libicns

Library for manipulation of macOS .icns resource format files

brewmacoslinux

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Library for manipulation of the macOS .icns resource format

icns2pngpng2icnsicontainericnsutil

Convert an .icns file to PNG images at all available resolutions$ icns2png -x icon.icns

Convert a PNG image to macOS .icns format$ png2icns output.icns input.png

Extract all icon sizes from an .icns file to individual PNG files$ icns2png -o output_directory icon.icns