Often when people link to my website on Facebook (www.frome.fm) it often automatically adds one of the images of our sponsors instead of chosing something more appropriate.
I have used the code found at http://jetpack.me/2013/07/12/add-a-default-image-open-graph-tag-on-home-page to make a functionality plugin however this does not seem to have worked.
Viewing the source html still shows the following:
<meta property="og:image" content="http://wordpress.com/i/blank.jpg" />
Instead of the image url I would prefer: