Mark,
To specify the title, description and image you want used when the Like is clicked, you need to use Open Graph tags, as you already mentioned. Open Graph integration in JFBConnect is enabled by default, but you can check the setting in the Social Configuration -> Open Graph tab. Then, all you need to do is add the following tag to your article to specify the information you want used:
{SCOpenGraph title=Title of Page}
{SCOpenGraph description=Description for page}
{SCOpenGraph image=http://site.com/link-to-image.jpg}
If you don't specify a title or description Open Graph tag, JFBConnect will automatically set the tags to the meta title and description that's set for the page.
It will take Facebook 24-48 hours to update the image for new like's, so if you try right away, you may not see a difference. You can use the debug tool to see what Facebook 'sees' on your page from the Open Graph tags:
developers.facebook.com/tools/debug
You can also use the Open Graph tab in the social configuration area to specify a default image, in case you haven't explicitly set one on a page using the tag above. This is good for using your logo or something, just to make sure some random image isn't shown. To do so, add the following tag into the defaults box:
image=http://site.com/good-default-image.jpg
For more about JFBConnect's Open Graph features, see:
www.sourcecoast.com/jfbconnect/features/...pen-graph-for-joomla
Hope that all explains, but if you have more questions, just let me know!
Alex