[Digital Jedi]

You actually do have a measure of control over which images are selected by Facebook. But you have to have certain parameters in place. For example, you need to have the necessary meta tags in your head code, like described here: http://stackoverflow.com/questions/1...-select-images. And I went ahead and used replacement variables to insert the namespaces, so as to pass validation.

I'm also on vB3, and this I what I put in my headinclude, in addition to adding the proper namespaces.

<!-- Facebook Meta Tags -->
<meta property="og:title" content="<if condition="$show['threadinfo']"><if condition="$pagenumber>1"><phrase 1="$pagenumber">$vbphrase[page_x]</phrase> :: </if>$threadinfo[prefix_plain_html] $threadinfo[title]<else /><if condition="$show['foruminfo']"><if condition="$pagenumber>1"><phrase 1="$pagenumber">$vbphrase[page_x]</phrase> :: </if>$foruminfo[title_clean]<else />$vboptions[hometitle]</if></if>" />
<meta property="og:site_name" content="$vboptions[bbtitle]" /> 
<meta property="og:url" content="$vboptions[homeurl]$_SERVER[SCRIPT_NAME]?$_SERVER[QUERY_STRING]" />
<meta property="og:description" content="<if condition="$show['threadinfo']">$threadinfo[preview]<else /><if condition="$show['foruminfo']">$foruminfo[description_clean]<else />$vboptions[description]</if></if>" />
<if condition="$show['threadinfo'] !=1"><if condition="$show['foruminfo'] !=1"><meta property="og:image" content="$vboptions[bburl]/images/fb-default.png" /></if></if>
<meta property="fb:app_id" content="YOUR-APP-ID-HERE" />
<!-- / Facebook Meta Tags -->

This is tailored to my site, and obviously you should get an app ID. (This helps with statistics.) Consult the Best Practices guide to get an understanding of what I've done here, and when you start adding tags, test them against the debugger. One of the things you might notice, if you look at my code and website in-depth, is I haven't yet created a suitable default image for pages that don't have a unique one. I put one in place, but Facebook isn't accepting it as such. In this case, Facebook is still choosing the best one based on it's internal config. And, oddly enough, we're still not sure why it doesn't honor this setup 100% of the time. But, even so, it's much more consistent that not having them at all.

--------------- Added [DATE]1421809672[/DATE] at [TIME]1421809672[/TIME] ---------------

Also note, you really only need to do this in one style. The default style guests see when they visit your website. This is the first style the Facebook crawler and the debugger will see, and will likely be the only one it checks.