Add screenshot due to popular requests

index.md

@@ -12,6 +12,8 @@
 
 __hello__ (also known as __helloSystem__) is a desktop system for creators with focus on simplicity, elegance, and usability. Its design follows the "Less, but better" philosophy. It is intended as a system for "mere mortals", welcoming to switchers from the Mac. [FreeBSD](https://www.freebsd.org/) is used as the core operating system. Please refer to [https://github.com/helloSystem/hello](https://github.com/helloSystem/hello) if you would like to learn more about the ideas and principles behind hello.
 
+![Screenshot](https://github.com/helloSystem/hello/blob/master/screenshots/20210210-desktop-0.4.png?raw=true)
+
 ```eval_rst
 .. toctree::
    :maxdepth: 3