I have built a mockup/demo of a chatview using yusuf cihan's Dynamic Components extension. It is not a finished product, but should show how to use the extension to generate messages with images and text.
This is built in App Inventor, uses only App Inventor blocks and components.
AIA file
AI2ChatView.aia (121.6 KB)
[EDIT]
With the latest version of Yusuf's extension, it is now possible to reverse the order of the cards after creating them, so that with a chat type project, you can have the latest post at the top, instead of hidden at the bottom