tedster - 10:50 pm on Oct 16, 2010 (gmt 0)
Here's what I'd try first:
In order to make sure that the preview is always correctly populated, you should add the tags shown below to the <head> element in your HTML code. If you don't tag your page, Facebook Share will grab the title of your page as specified in the <title> tag, and will create a summary description from the first text that appears in the body of your page. A list of thumbnails will all be selected from available images on your page.
You can control the exact title, description, and thumbnail that Facebook Share uses by adding the following meta tags to the <head> element in your page:
<meta property="og:title" content="title" />
<meta property="og:description" content="description" />
<meta property="og:image" content="thumbnail_image" />