Compress png and remove unused img (#2706)

* Losslessly compress PNG files

Before: 1,17 MB (1.228.084 bytes)
After:  1,13 MB (1.194.642 bytes)

* Rename image for consistency.

* Delete the unused mestro.png

pages/examples/projects.html

@@ -784,7 +784,7 @@
                                   <img alt="Avatar" class="table-avatar" src="../../dist/img/avatar3.png">
                               </li>
                               <li class="list-inline-item">
-                                  <img alt="Avatar" class="table-avatar" src="../../dist/img/avatar04.png">
+                                  <img alt="Avatar" class="table-avatar" src="../../dist/img/avatar4.png">
                               </li>
                           </ul>
                       </td>
@@ -952,7 +952,7 @@
                                   <img alt="Avatar" class="table-avatar" src="../../dist/img/avatar3.png">
                               </li>
                               <li class="list-inline-item">
-                                  <img alt="Avatar" class="table-avatar" src="../../dist/img/avatar04.png">
+                                  <img alt="Avatar" class="table-avatar" src="../../dist/img/avatar4.png">
                               </li>
                           </ul>
                       </td>
@@ -1005,7 +1005,7 @@
                                   <img alt="Avatar" class="table-avatar" src="../../dist/img/avatar.png">
                               </li>
                               <li class="list-inline-item">
-                                  <img alt="Avatar" class="table-avatar" src="../../dist/img/avatar04.png">
+                                  <img alt="Avatar" class="table-avatar" src="../../dist/img/avatar4.png">
                               </li>
                               <li class="list-inline-item">
                                   <img alt="Avatar" class="table-avatar" src="../../dist/img/avatar5.png">
@@ -1067,7 +1067,7 @@
                                   <img alt="Avatar" class="table-avatar" src="../../dist/img/avatar3.png">
                               </li>
                               <li class="list-inline-item">
-                                  <img alt="Avatar" class="table-avatar" src="../../dist/img/avatar04.png">
+                                  <img alt="Avatar" class="table-avatar" src="../../dist/img/avatar4.png">
                               </li>
                           </ul>
                       </td>
@@ -1117,7 +1117,7 @@
                       <td>
                           <ul class="list-inline">
                               <li class="list-inline-item">
-                                  <img alt="Avatar" class="table-avatar" src="../../dist/img/avatar04.png">
+                                  <img alt="Avatar" class="table-avatar" src="../../dist/img/avatar4.png">
                               </li>
                               <li class="list-inline-item">
                                   <img alt="Avatar" class="table-avatar" src="../../dist/img/avatar5.png">
@@ -1176,7 +1176,7 @@
                                   <img alt="Avatar" class="table-avatar" src="../../dist/img/avatar3.png">
                               </li>
                               <li class="list-inline-item">
-                                  <img alt="Avatar" class="table-avatar" src="../../dist/img/avatar04.png">
+                                  <img alt="Avatar" class="table-avatar" src="../../dist/img/avatar4.png">
                               </li>
                           </ul>
                       </td>
@@ -1232,7 +1232,7 @@
                                   <img alt="Avatar" class="table-avatar" src="../../dist/img/avatar3.png">
                               </li>
                               <li class="list-inline-item">
-                                  <img alt="Avatar" class="table-avatar" src="../../dist/img/avatar04.png">
+                                  <img alt="Avatar" class="table-avatar" src="../../dist/img/avatar4.png">
                               </li>
                               <li class="list-inline-item">
                                   <img alt="Avatar" class="table-avatar" src="../../dist/img/avatar5.png">