When I put down {{#setmainimage:Filename.ext}} what I get in the og:image is not the actual image but a thumb of that image.
Example:
If I put down {{#setmainimage:Filename.png}} I get:
<meta property="og:image" content="http://sitename.com/wiki/images/thumb/5/5d/Filename.png/105px-Filename.png" />
instead of simply
<meta property="og:image" content="http://sitename.com/wiki/images/5/5d/Filename.png" />
Any ideas what can cause this?