Gimp Script-Fu for exporting favicons from current image as provided by favicomatic.
To use, put the script in a directory acknowledged by gimp for
script-fu like ~/.gimp-x.x/scripts and refresh scripts (Menu →
Filters → Script-Fu → Refresh Scripts). Then use Export favicons from Automation menu. Once generated, use the
following snippet with appropriate path
<link rel="apple-touch-icon-precomposed" sizes="57x57" href="/favicons/apple-touch-icon-57x57.png" />
<link rel="apple-touch-icon-precomposed" sizes="114x114" href="/favicons/apple-touch-icon-114x114.png" />
<link rel="apple-touch-icon-precomposed" sizes="72x72" href="/favicons/apple-touch-icon-72x72.png" />
<link rel="apple-touch-icon-precomposed" sizes="144x144" href="/favicons/apple-touch-icon-144x144.png" />
<link rel="apple-touch-icon-precomposed" sizes="60x60" href="/favicons/apple-touch-icon-60x60.png" />
<link rel="apple-touch-icon-precomposed" sizes="120x120" href="/favicons/apple-touch-icon-120x120.png" />
<link rel="apple-touch-icon-precomposed" sizes="76x76" href="/favicons/apple-touch-icon-76x76.png" />
<link rel="apple-touch-icon-precomposed" sizes="152x152" href="/favicons/apple-touch-icon-152x152.png" />
<link rel="icon" type="image/png" href="/favicons/favicon-196x196.png" sizes="196x196" />
<link rel="icon" type="image/png" href="/favicons/favicon-96x96.png" sizes="96x96" />
<link rel="icon" type="image/png" href="/favicons/favicon-32x32.png" sizes="32x32" />
<link rel="icon" type="image/png" href="/favicons/favicon-16x16.png" sizes="16x16" />
<link rel="icon" type="image/png" href="/favicons/favicon-128x128.png" sizes="128x128" />
<meta name="application-name" content=" "/>
<meta name="msapplication-TileColor" content="#FFFFFF" />
<meta name="msapplication-TileImage" content="/favicons/mstile-144x144.png" />
<meta name="msapplication-square70x70logo" content="/favicons/mstile-70x70.png" />
<meta name="msapplication-square150x150logo" content="/favicons/mstile-150x150.png" />
<meta name="msapplication-wide310x150logo" content="/favicons/mstile-310x150.png" />
<meta name="msapplication-square310x310logo" content="/favicons/mstile-310x310.png" />