To use the favicons insert into your html head section some of these tags accordly to your needs.
<!-- For old IEs -->
<link rel="shortcut icon" href="favicon.ico" />
<!-- For new browsers - multisize ico -->
<link rel="icon" type="image/x-icon" sizes="16x16 32x32" href="favicon.ico">
<!-- For iPad with high-resolution Retina display running iOS ≥ 7: -->
<link rel="apple-touch-icon-precomposed" sizes="152x152" href="favicon-152.png">
<!-- For iPad with high-resolution Retina display running iOS ≤ 6: -->
<link rel="apple-touch-icon-precomposed" sizes="144x144" href="favicon-144.png">
<!-- For iPhone with high-resolution Retina display running iOS ≥ 7: -->
<link rel="apple-touch-icon-precomposed" sizes="120x120" href="favicon-120.png">
<!-- For iPhone with high-resolution Retina display running iOS ≤ 6: -->
<link rel="apple-touch-icon-precomposed" sizes="114x114" href="favicon-114.png">
<!-- For iPhone 6+ -->
<link rel="apple-touch-icon-precomposed" sizes="180x180" href="favicon-180.png">
<!-- For first- and second-generation iPad: -->
<link rel="apple-touch-icon-precomposed" sizes="72x72" href="favicon-72.png">
<!-- For non-Retina iPhone, iPod Touch, and Android 2.1+ devices: -->
<link rel="apple-touch-icon-precomposed" href="favicon-57.png">
<!-- For Old Chrome -->
<link rel="icon" href="favicon-32.png" sizes="32x32">
<!-- For IE10 Metro -->
<meta name="msapplication-TileColor" content="#FFFFFF">
<meta name="msapplication-TileImage" content="favicon-144.png">
<!-- Chrome for Android -->
<link rel="icon" sizes="192x192" href="favicon-192.png">
For more informations about favicons consult The Favicon Cheat Sheet by Audrey Roy.