No image when posting comments to a wall

We're working on a way to specify more information about the page your liking. There are a set of meta tags that can be inserted into the head section which help tell Facebook extra information about the page, like the image to use.

Unfortunately, we don't have anything for what you're looking for yet, but something should be available soon, near the time of the 3.1 release (due very soon).

Right now, the plugin can't insert the tags. We're expecting to get this implemented in the 3.2 release now, along with some other updates to the whole slew of social plugins. Until then, the tags that need to be inserted can be found on the following page:
developers.facebook.com/docs/opengraph

Hope this helps get you started, but if you have any questions, let us know.