How do I add og:image script in meta? My facebook is grabbing the wrong image.

I try to adding this open graph image in my head.

&lt;meta property="og:image" content="&lt;?= $_GET['image'] ?&gt;" /&gt;


and

&lt;meta property="og:image" content="&lt;?php echo $image; ?&gt;"/&gt;


but the content image path is not shown. 
It became this 

&lt;meta property="og:image" content="" /&gt;


I want it to be like this.
If the article A have image a_name.jpg, the meta will be &lt;meta property="og:image" content="/images/a_name.jpg"/&gt;

If the article B have image b_name.jpg, the meta will be &lt;meta property="og:image" content="/images/b_name.jpg"/&gt;
You need to supply the tag the full URL to the image. If you install the Metatag module not only can you have full control over keyword, description, etc. but also all the og tags too per node.