JFBConnect upgrade deleted all my visitor comments and likes :(

What version did you upgrade from, do you know?

The Comments box did change recently by Facebook. Previously, you were required to set a parameter called 'xid' which was a unique identifier for each comment box. The new comment box uses the URL of the page the comment is being placed on (or where they should show). The new system is obviously much more logical, but there's no way to use both. However, JFBConnect still has the ability to create the 'old' xid parameter on a page so that previous comments can still remain. It will take a little bit of manual configuration to add the Comment box to pages where you want to save the old comments though.

The Likes shouldn't have really changed. We did add some logic to guess a better URL, which prevents spreading your likes out across multiple pages that Joomla can resolve to the same page, like:
index.php?option=com_content&view=article&id=12 (non-sef route to article 12)
index.php?option=com_content&view=article&id=12&Itemid=24 (non-sef route to article 12 from menu item 24)
/category/article (SEF route to article)

Before, the Like button may have created individual 'Like' buttons for all 3 pages, which wasn't ideal. Again, we can help you figure out 'where' your Likes and Comments were, and then, if you want, you can manually add {JFBCLike url=http://oldurl} and {JFBCComments xid=1234} to all the pages where you had comments/Likes you want to save.

Hope this helps explain. We sincerely hope (and think) this is the last major change that Facebook will be making to the Comments box. Glad they made it.. wish they had a better way to migrate comments forward to the new system though.

Sorry for the technical babble.

Basically, for each page that has comments, a unique ID needs to be specified to identify that page to Facebook so that all comments are 'attached' to that page. This is good if you have a blog view, with many articles, each comment box can still be attached to the article the comment box is for. In late March, Facebook changed how they identify each page. In 3.2.0, we changed to the new method that Facebook requires. While possible, it can be difficult to retrieve the comments that used the 'old' method. If you had a page with a lot of comments, we can help you do this, but in general, you should go with the new comment box for all new pages, or pages that had only a few comments. It sucks, we agree. Facebook shouldn't be changing this identifier anymore, which will be nice.

As for the image that's posted, that's determined by the Open Graph tag. If you go into the Social Configuration -> Open Graph tab, you can set it up so that JFBConnect will pick the first image in an article to use as the image for that page. Alternatively, you can simply type:
{JFBCGraph image=http://domain.com/imagetouse.jpg}
Anywhere on the page, and that's the image that will be used.

The Open Graph tags describe to Facebook how to display your page in someone's wall. If you aren't specifying any defaults (in the Open Graph configuration area of JFBConnect) or on each page, then Facebook will 'guess' what the best title, description and image is to represent each page that's shared. You can see how Facebook sees your pages by using their linter tool. As you add Open Graph tags, you'll be able to verify they are setup how you want with this tool:
developers.facebook.com/tools/lint

Hope that helps explain, but if you need more information, just let us know!