How to update facebook open graph image

Question

Say if you have set the facebook image for your webpage via the meta tag of the open graph protocol like this:

Answer 1

Facebook stores your image into their own image on their servers, and then caches it for 24h. The cache delay might change in the future, so to check it just open the image that facebook creates from your image and check its "max-age" value in the http headers. So if you change your image, facebook will not update its version until 24h even if you use this link http://developers.facebook.com/tools/debug to force the data fetching.

To solve this, if you need to see the effect of your change right away you should rename your image. So if the old version was rock.jpg name it rock2.jpg then use this link http://developers.facebook.com/tools/debug to get facebook to create a new image from your updated image. This will update immediately your webpage's facebook image in the facebook share.