Take a look at this article which discusses how to set multiple images on the og: tag for the facebook share utility. Most importantly take a look at this solution:
og:image meta tag you are using is called by Facebook's servers after the user clicks your share button. So if you are trying to change this and have the person click the share button, this won't work. If you want to support multiple
og:images on your page you could use different query parameters for each image.
http://www.mysite.com/mypage?image=myimage.jpg would render the metatag like
<meta property="og:image" content="http://www.mysite.com/myimage.jpg" />
Then you could also have for example:
that would render the metatag like
<meta property="og:image" content="http://www.mysite.com/anotherimage.jpg" />
Another way you could do this is would just be to ask the user for stream_publish permission and use the Graph API to send the post directly to facebook yourself. You can find out more about this approach here: http://developers.facebook.com/docs/reference/api/post
Let me know if this doesn't clear things up.
the Telerik team
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