replace NewPipe on GitHub PNG file with SVG

fix typos

index.html

@@ -107,7 +107,7 @@ <h3>the lightweight<br>YouTube experience<br>for Android</h3>
                     <div class="col-sm-6">
                         <p><strong>Do you like watching videos on YouTube<br>but looking for a simple app to do that?</strong></p>
                         <p class="text-justify-md"><span class="red">NewPipe</span> has been created with the purpose of getting the original YouTube experience on your smartphone without annoying ads and questionable permissions.</p>
-                        <p>The application is Open Source and you can check on it at <a href="https://github.com/TeamNewPipe/NewPipe/">GitHub</a>.</p>
+                        <p>The application is open source and you can check on it at <a href="https://github.com/TeamNewPipe/NewPipe/">GitHub</a>.</p>
                     </div>
                 </div>
             </div>
@@ -594,7 +594,7 @@ <h4>F-Droid</h4>
                 <div class="col-lg-12 tile" id="tile-opensource">
                     <div class="tile-media">
                         <a href="https://github.com/TeamNewPipe/NewPipe">
-                            <img src="/img/newpipe_on_github.png" class="img-responsive" />
+                            <img src="/img/newpipe_on_github.svg" class="img-responsive" />
                         </a>
                     </div>
                     <div class="tile-description">
@@ -632,7 +632,7 @@ <h4>Why NewPipe is free</h4>
                         <li>NewPipe is powered by a growing community</li>
                         <li>Our goal is to make the internet a more free (libre) place and open it for everyone</li>
                         <li>Your donation cover a majority our costs</li>
-                        <li class="text-success">F-Droid, WebLate, Sentry and other companies offer their services to Open Source projects for free</li>
+                        <li class="text-success">F-Droid, WebLate, Sentry and other companies offer their services to open source projects for free</li>
                     </ul>
                 </div>
                 <div class="col-md-6 tile tile-right" id="tile-like-np">