How to include a thumbnail in the HTML of a page 

If we had a registry for emerging web standards, we would have added one to it yesterday. The emerging format has been proposed by Facebook, supported by Digg and ratified by FriendFeed, and yesterday -- Scripting News. The format allows a photo-oriented web site or individual web page to include a thumbnail, so that when it's referred to by a site such as Digg or FriendFeed the representation may include that thumbnail.

I support this because: 1. I have such a website. 2. And I believe that sites like Digg, FriendFeed, Twitter are more attractive and useful when they include little bits of color graphics. It's the same principle that guided Apple to create the Macintosh in 1984, almost 25 years ago, when the current form of user interface was character-based.

To support this format, include a <link> element like this:

<link rel="image_src" href="http://static.flickrfan.org/afp/thumbnails/2009/01/10/trwas2108818.jpg" type="image/jpeg" data-width="150" data-height="122" />

And some other metadata, as explained on the Digg site.

View source on this page to see a real-world example.

I tested it with both Digg and FriendFeed and found that it works, although there at least one place where FriendFeed could support it, but they don't, yet.

Update: James Holderness says this came from Facebook, and Digg says so on their site, but the page they link to doesn't seem to say anything about thumbnails. I searched and found a citation here, but he doesn't link to any Facebook spec. I think it's fair to say Facebook supports it. I'll test now. Result: Yes! Here's a screen shot of how they appear in my Facebook profile. So they must be added to the list, which I will do now.