You need to insert a tag like below into the HTML output of the page so that JFBConnect can detect it and determine the og:image tag to insert into the page:
{SCOpenGraph image=http://yoursite.com/link-to-some-image.jpg}
The thing you need to determine is what the actual image is that needs to be inserted into that tag. If you're able to use PHP, the code would be like what I posted above, where $firstImage has some code to grab the first image from SobiPro.
I guess the best question to ask the SobiPro developers is:
* Using PHP, how can I get the main image for a page?
* Once I have that, how can I use that image URL in a custom string that I want to display on the page?
With those 2 answers, I could help you create the right code you'd need to add wherever/however they tell you.
I hope that helps,
Alex