You are missing this section of code in your file:
<?php
$blogContent = WA_getCMSContent($database_PowerCMSConnection, $PowerCMSConnection, 'blogPost', 'Content', false, $row_Recordset1['ContentPageSetOrder']);
$blogImage = preg_match('/<img [^\r\n]* src="([^"]*)/i',$blogContent,$retVal);
?>
That is what picks up the image from the cms content so you can add it to the og:image tag. It should appear directly above the og:image tag.