Heroes84 Heroes84 - 1 month ago 13
HTML Question

What is <link rel="image_src">

Today I came across a

<link rel="image_src">
tag. I don't know about it, so I use google. Google tell me that this tag are similar to
og:image
. So I came to open graph main site to read about it http://ogp.me/, but i found nothing about link
rel="image_src"
. So this tag is replacement to meta
property="og:image"
or is in special tag in another specification ? How use this tag or for what is used?

Answer

The rel attribute specifies the type of the link, i.e. the kind of the relationship between the document and the linked resource. Usually just a few keywords, like stylesheet and icon, are used. Although many other keywords have been proposed and registered, most of them are write-only: they are meant to express something, but nobody cares (no software uses the information).

The extension mechanisms of HTML5 include, in the description of link types, a somewhat obscure mechanism that allows, in theory, anyone register his favorite keyword in the existing rel values wiki to make documents using it as rel value “conforming”.

And image_src has indeed been registered there, with the information that it is used to “specify a Webpage Icon for use by Facebook, Yahoo, Digg, etc.”, no specification has been identified but an article about it is linked to, and it is “probably redundant with rel=icon”.