Codebank

Use Terminal to combine multiple PNG images into a single .ico icon file. Open Terminal, navigate into the folder containing the image files, then run this command:

convert 16.png 32.png 48.png 256.png favicon.ico

Note: since the most recent system update that uses ImageMagick 7 you now need to preface the command with 'magick' instead of 'convert':

magick 16.png 32.png 48.png 256.png favicon.ico

Depending on the colour profile of the PNG files you will sometimes get the error magick: Cannot write image with defined png:bit-depth or png:color-type. In this case you can add the -compress none option:

magick -compress none 16.png 32.png 48.png 256.png favicon.ico