A method of storing a preview image of a document shared over a social media service includes receiving at a server a first notification that a document stored on the server is being shared on a post by a first user on the social media service, where the first notification includes information identifying the first user. The method further includes generating a thumbnail image from the document, where the thumbnail image is stored in the document metadata and is a representative image of a first version of the document at the time the user shares the document, associating the thumbnail image with a URL, where the URL has an access control list that includes the first user, and sending the URL from the server to the social media service.