add pngs to dir and README

README.md

@@ -72,6 +72,21 @@ A simple showcase how the controller can be addressed after
   on them. They are currently unsupported.
 - `controller` represents the `goSDN-controller`.
 
+<div align="center" style="margin-bottom:3em; margin-top:4em">
+  <img src="documentation/figures/overview/updated_controller_architecture_overview.drawio.png" />
+    <p> Overview of the controller architecture</p>
+</div>
+
+<div align="center" style="margin-bottom:3em; margin-top:4em">
+  <img src="documentation/figures/nucleus/updated_controller_architecture_nucleus.drawio.png" />
+  <p> Detailed view of nucleus </p>
+</div>
+
+<div align="center" style="margin-bottom:3em; margin-top:4em">
+  <img src="documentation/figures/plugins/plugin-device-interaction.drawio.png" />
+  <p> Detailed view of plugin mechanism</p>
+</div>
+
 ---
 
 ## Concepts