title: How to use local file as thumbnail in DiscordJS embedded message?
body: <p>Is it possible to use a local file as a thumbnail for an embedded message with DiscordJs?</p>
  
  <pre><code>"thumbnail": {
    "url": "../img/025.png"
  },
  </code></pre>
  
  <p>This doesn't seem to work.</p>
  
  <pre><code>(node:34721) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1):  
  DiscordAPIError: Invalid Form Body 
  embed.thumbnail.url: Not a well formed URL.
  </code></pre>
  
  <p>Normal URL's do work however.</p>