title: ' Unable to download all specified images.' when trying to run a notification on a chrome extension
body: <p><strong>Script:</strong></p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code> chrome.notifications.create(
      'name-for-notification',{   
      type: 'basic', 
      iconUrl: 'icon4.png',
      title: "This is a notification", 
      message: "hello there!" 
      });</code></pre>
  </div>
  </div>
  </p>
  
  <p>Everytime I run it, I get the error </p>
  
  <blockquote>
    <p>Unchecked runtime.lastError while running notifications.create: Unable to download all specified images.</p>
  </blockquote>
  
  <p>But here's the thing, "icon4.png" is in the same file as my script, background. 
  <a href="https://i.stack.imgur.com/Qh61D.png" rel="nofollow noreferrer">See for yourself.</a></p>
  
  <p>I don't know why it's not working, the icon is there. I've tried using this aswell:</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code> chrome.notifications.create(
          'name-for-notification',{   
          type: 'basic', 
          iconUrl: 'http://www.filehosting.org/file/details/671921/icon4.png',
          title: "This is a notification", 
          message: "hello there!" 
          });</code></pre>
  </div>
  </div>
  </p>
  
  <p>And it still doesnt work!</p>
  
  <p>And yes, I have the notifications permission set in my manifest.</p>