choice of image with facebook recommend ?

Hi,
I am using facebook recommend page with cb connect and cb content with substitutions.
It works really fine and I like it (my users too)

But it seems, it takes always the first image on the page for the facebook.
How can I decide, which image should be taken?
Is there someone who can give me a help for that?

Facebook determines its image by first checking Open Graph Protocol then if that's missing it uses the first image found. You can specify Open Graph Protocol in the "Metadata" parameter. Example as follows.

Further Open Graph Protocol information can be found below.

developers.facebook.com/docs/opengraph/

Thanks for your help. I will try. My problem is, that my english is unsufficient for so long informations