shivanshd51/post-feed-project-mern ? reverse-engineered prompt

Build me a simple full stack post feed app where people can upload a photo, add a short caption, and see the new post show up right away at the top of the feed.

I want a clean black and white interface, with a preview of the image before posting, a caption box with a character counter, and an empty state when there are no posts yet. The posts should be saved in a database so they stay there after refresh, and the images should be stored in the cloud instead of directly in the app. Use a React frontend and a Node and Express backend, and make sure the frontend talks to the backend with a basic API for getting all posts and creating a new one. If you need to check current docs for anything, go ahead and look them up online.