Add new portfolio images

Author: peterdesmet

images/bird-migration-flow-visualization.png

@@ -69,7 +69,7 @@ <h1 class="text-center">We offer expertise in data visualization and publication
                                 <h3>Rolling blackout plan</h3>
                                 <p>Own project</p>
                             </div>
-                            <img src="" alt="screenshot">
+                            <img src="images/rolling-blackout-belgium.png" alt="screenshot">
                         </a>
                     </div>
 
@@ -89,7 +89,7 @@ <h3>Bird migration flow visualization</h3>
                                 <h3>Scuba diving citizen science observations</h3>
                                 <p>Diveboard</p>
                             </div>
-                            <img src="" alt="screenshot">
+                            <img src="images/scuba-diving-citizen-science-observations.jpg" alt="screenshot">
                         </a>
                     </div>
                 </div>