Update 'README.md'

Added screenshot to README, hosted on my s3 bucket.

README.md

@@ -2,7 +2,7 @@
 
 Welcome to **TUI Launcher**! A simple, yet beautiful and customizable Terminal User Interface (TUI) for launching your favorite command-line programs.
 
-![TUI Launcher Demo](https://user-images.githubusercontent.com/12345/67890.gif) <!-- Replace with an actual demo GIF -->
+![A screenshot of TUI Launcher in action](https://m1s5.c20.e2-5.dev/files/images/tui-launcher-screenshot.png)
 
 ## ✨ Features