The post is also available in: Swedish

Summarizes ways to link pictures to the website, such as favicons and other.

Common favicon
16×16

<link type="image/x-icon" rel="shortcut icon" href="favicon.ico" />

Animated favicon
16×16 GIF file
Doesn’t work in all browsers

<link type="image/gif" rel="shortcut icon" href="favicon.gif" />

Iphone/ipad/ipod
57×57 PNG file

<link type="image/png" rel="apple-touch-icon" href="touch-icon.png" />

Specifying other resolution to better fit the different units

<link rel="apple-touch-icon" sizes="72x72"   href="ipad.png" />

<link rel="apple-touch-icon" sizes="114x114" href="iphone4.png" />

When the page is shared socially, eg: Facebook and Google+

<link rel="image_src" type="image/png" href="social-icon.png" />