add preview screenshot image

index.html

@@ -4,6 +4,7 @@
     <title>ngn/apl</title>
     <meta charset="UTF-8">
     <meta http-equiv="refresh" content="1;url=web/index.html">
+    <meta property="og:image" content="ngn-apl-screenshot.png" />
 
     <!-- Disable cache - source: https://stackoverflow.com/a/65475919/12947681 -->
     <meta http-equiv='cache-control' content='no-cache'> 

readme.md

@@ -1,13 +1,11 @@
 # ngn/apl
 
-This is a fork of [ngn/apl](https://github.com/abrudz/ngn-apl).
+Try using it online **[here](https://sohang3112.github.io/ngn-apl)**. It can also be used as a [PWA (Progressive Web App)](https://developer.mozilla.org/en-US/docs/Web/Progressive_web_apps/Guides/What_is_a_progressive_web_app) on a computer / phone - even without internet!
 
-This fork adds the ability to install & use this as a [PWA (Progressive Web App)](https://developer.mozilla.org/en-US/docs/Web/Progressive_web_apps/Guides/What_is_a_progressive_web_app).
+![Screenshot](ngn-apl-screenshot.png)
 
 ----
 
-**[Demo](https://sohang3112.github.io/ngn-apl)**
-
 An [APL](https://en.wikipedia.org/wiki/APL_%28programming_language%29) interpreter written in JavaScript.
 Runs in a browser or [NodeJS](https://nodejs.org/).
 
@@ -20,7 +18,7 @@ prototypes, modified assignment (`x+←1`), control structures (`:If`), object-o
 Used in [Paul L Jackson's web site](https://plj541.github.io/APL.js/), [repl.it](https://repl.it/languages/APL),
 and [tio.run](https://tio.run/#apl-ngn).
 
-# Offline usage
+# Offline usage with NodeJS
 
 Run `apl.js` with [Node](https://nodejs.org/) to start a REPL:
 

web/index.html

@@ -4,6 +4,7 @@
    <meta charset=utf-8>
    <title>ngn/apl</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
+   <meta property="og:image" content="../ngn-apl-screenshot.png" />
 
    <!-- Disable cache - source: https://stackoverflow.com/a/65475919/12947681 -->
    <meta http-equiv='cache-control' content='no-cache'>