create images directory if it does not exist

ros3rag.placeB/src/main/java/de/tudresden/inf/st/placeB/MainB.java

@@ -36,6 +36,20 @@ public class MainB extends SharedMainParts<MqttHandler, WorldModelB> {
     new MainB(configFile).run();
   }
 
+  @Override
+  public void run() throws Exception {
+    // ensure that directory "images" exists
+    File imagesDirectory = Paths.get("images/").toFile();
+    if (!imagesDirectory.exists()) {
+      boolean success = imagesDirectory.mkdir();
+      if (!success) {
+        logger.debug("Failed to create directory {}", imagesDirectory.getAbsolutePath());
+      }
+    }
+
+    super.run();
+  }
+
   @Override
   protected MqttHandler createMqttHandler() {
     return new MqttHandler("mainHandlerB");