I am developing a Facebook application that stores into MySQL the photo[id].
I am using Facebook’s Graph API to retrieve all of the user’s photos and by a radio button the selected photo[id] is stored into mysql.
The problem is, how should I display the image’s source by the id stored?
You inspect the Graph Object for that id,
For example a photo from facebook.com/facebook
This will return a JSON response for which you can choose the size you desire for the source.
For more information see, http://developers.facebook.com/docs/reference/api/photo/
For example in the PHP SDK