facebook linking of article - getting right article to display

when i link an article on facebook, it doesn't always (if ever) pick the right photo / article to "show" on facebook. i know i've had to create some H-tags to get the right photo to show up on a http://www.mysite.com posting, but not sure what i need to do to easyblog posts to ensure that facebook is picking up the right post to show with the link to the story.

is this something for easyblog or joomla itself? appreciate the help!