1. A method comprising: by one or more computing devices, detecting entry of an identifier of an object by a first user participating in a message session, wherein the detecting is based on the identifier being in a pre-determined text format, the message session comprising a text message including the identifier; by the computing devices, determining a first node in a social graph of a social-networking system that corresponds to the object based at least in part on the identifier of the object, the graph comprising a plurality of nodes and edges connecting the nodes, wherein a second node in the graph corresponds to the first user; by the computing devices, accessing one or more images corresponding to the object associated with the first node in the social graph; and by the computing devices, sending the text message to a second user in which the identifier included in the text message is replaced with an in-line image within the text message, wherein the in-line image comprises at least one of the accessed images associated with the first node in the social graph corresponding to the object.