link to images in core

docs/modules/core/pages/gui/nifty_gui_java_layout.adoc

@@ -585,7 +585,7 @@ When you preview this code in the jMonkeyEngine SDK, our tutorial demo should lo
 TIP: Remove all lines that set background colors, you only needed them to see the arrangement.
 
 
-image::jme3/advanced/nifty-gui-simple-demo.png[nifty-gui-simple-demo.png,width="",height="",align="center"]
+image::gui/nifty-gui-simple-demo.png[nifty-gui-simple-demo.png,width="",height="",align="center"]
 
 
 Your `Screen.java` file should look like this:

docs/modules/core/pages/gui/nifty_gui_xml_layout.adoc

@@ -412,7 +412,7 @@ See also:
 When you preview this code in the jMonkeyEngine SDK, our tutorial demo should looks as follows: A start screen with two buttons, and a game screen with a simple HUD frame and a blue cube (which stands for any jME3 game content).
 
 
-image::jme3/advanced/nifty-gui-simple-demo.png[nifty-gui-simple-demo.png,width="",height="",align="center"]
+image::gui/nifty-gui-simple-demo.png[nifty-gui-simple-demo.png,width="",height="",align="center"]
 
 
 Compare this result with the layout draft above.