The document discusses two options for implementing the display of video and photo previews in chat windows when links are shared. Option 1 has the sender retrieve the preview data and send it to the receiver. This requires changing the chat message format but reduces load as data only needs to be retrieved once. Option 2 has each user retrieve preview data independently when they receive a link. This does not require changing the message format but results in the data being retrieved twice. The implemented prototype follows Option 2, retrieving data independently on the sender and receiver sides. Code modifications are described to the ConversationChatPanel class to check for links and spawn a thread to call the GetLinkData method.