The Open Graph Protocol aims at integrating any website into a global social graph. The main idea behind this movement is to provide a simple and common way to share contents through social networks, allowing social network providers to manage incoming data from billions of websites, based on the standard rules laid down by the protocol.

Starting from version 5.1.1, b2evolution supports the og:image and og:type open graph tags.

When enabled, the permalink page of a given post (disp=single) will include one <meta property="og:image" content="http:/url.to/your/image.jpg" /> tag for each image attached to it. Additionally, each post will be marked with <meta property="og:type" content="article" /> (as required by FaceBook).

That way, when a post is shared on a social network that supports the Open Graph protocol, the first image will be automatically added as a thumbnail. If there are more than one attached images, most social networks will allow the user will to select the most appropriate thumbnail in between those images.

This feature is fully supported by the following social networks:

• Facebook - They also have a debugger that is great for testing: https://developers.facebook.com/tools/debug/og/object/
• Google+
• LinkedIn

Please read this page if you would like to know how to enable/disable this feature.

Caveats

• Facebook seems to have a problem if your image URL or image name has a space in it. Also depending on the size of the image, it will be used differently.