I have a default image in my open graph configuration. I also use the tag in my articles to specify a more correct image.
In the open graph defaults, I specify image=http://www.worldcon76.org/images/FBImage.png
In the article, I have {SCOpenGraph image=http://www.worldcon76.org/images/guests/Spider.jpg}
In the source of the page, though, BOTH are sent, causing Facebook to use the default value.
<meta property="og:image" content="
www.worldcon76.org/images/guests/Spider.jpg"/>
<meta property="og:image" content="
www.worldcon76.org/images/FBImage.png"/>
I thought using the SCOpenGraph would OVERRIDE the default. I'd like that to happen, since Facebook is picking the wrong image for shares.
Default Facebook image always being used
Try the workaround I suggested and let us know if you still have issues until a new setting gets put in. 
