When I check the source of a post on my website I see two og:image tags. The first og:image tag on singleposts points to my header image, and the second og:image tag points to the image attached to the post.
Apparently the header image is to small for facebook, so it shows the attached image, but this is not the case with Google+ og when sharing on Scoop.it. Here I have the ability to choose between the two, but the standard is the header image. Is there any way I can change this, so that the attached image is shown by default? Or can I change the first og:image from showing the header image to showing a different image? I dont see any og:image tags when looking in header.php